A nano-suspension containing bifenthrin and its preparation method

Abstract

This invention discloses a nanoscale suspension containing bifenthrin, the raw materials of which include a dispersant consisting of a cationic polymer and an anionic naphthalene sulfonate formaldehyde condensate. The combination of the two can effectively improve the grinding efficiency (hereinafter referred to as grinding efficiency) of the bifenthrin-containing suspension during the preparation process, as well as the stability of the prepared bifenthrin-containing suspension, such as particle size storage stability and suspension rate.

Description

Technical Field

[0001] This invention belongs to the field of pesticide suspension technology, specifically relating to a nano-suspension containing bifenthrin and its preparation method. Background Technology

[0002] Pesticide suspensions (SC) are viscous suspensions composed of active ingredients and various adjuvants. The particle diameter is extremely small, reaching the micrometer level (generally with an average particle size of <5 micrometers). They can be used by diluting with water. They can also be used for aerial spraying. They are easy to use, have less environmental pollution, and are one of the main formulations of pesticides.

[0003] Bifenthrin is a novel pyrethroid insecticide and acaricide developed by FMC Corporation in the United States. It is characterized by strong knockdown effect, broad insecticidal spectrum, high efficiency, and long residual effect. It mainly acts through contact and stomach poison, without systemic action, and can be used to control cotton bollworm, psyllid, pink bollworm, tea geometrid moth, tea hairy caterpillar, etc.

[0004] In practical agricultural applications, pests have developed certain resistance to pesticides after long-term use. [Reference [1] Hu Yanyue, Sun Yang, Zou Zhiwen, et al. Resistance of citrus psyllids in Jiangxi Province to five conventional pesticides [J]. Journal of Applied Entomology, 2022(002):059.] At present, the main way to solve this problem in domestic formulations is to combine different chemical pesticides (such as thiamethoxam, pyrethroid, etc.) to expand the insecticidal range, enhance toxicity, and thus improve the pest control ability. For example, in patent application literature one, a suspension containing bifenthrin and flufenoxuron is disclosed, which improves the insecticidal and disease prevention effect by using bifenthrin and flufenoxuron as single agents. However, the particle size of bifenthrin suspensions on the market is currently controlled at the micron level (generally 3-5μm), which leads to huge deficiencies in the water dispersion performance, target deposition rate, and pesticide utilization of the bifenthrin.

[0005] Nanopesticides are one way to achieve excellent water dispersion, high target deposition rate, and high pesticide utilization. Nanopesticides are a pesticide form in which active ingredients exist at the nanoscale through nanotechnology and polymer carrier materials, or where active ingredients are loaded onto nanocarriers.

[0006] Currently, sand milling is the main method for industrializing nano-pesticides. However, nano-suspensions prepared by sand milling have smaller particle sizes and more intense Brownian motion, which is accelerated by increased temperature, thus posing a greater risk of particle size growth during storage. Furthermore, bifenthrin is a low-melting-point (68-70.6℃) and highly lipophilic active ingredient (oil-water partition coefficient logP 6.66), making it difficult to disperse and suspend in water. This leads to several issues: during nano-sizing via sand milling, it easily forms a paste or crystallizes, resulting in extremely low grinding efficiency. Even if nano-sizing is achieved through sand milling, the resulting suspension exhibits extremely poor thermal stability, easily leading to severe abnormalities such as crystallization and agglomeration. These problems become more pronounced with higher active ingredient content, further limiting the increase in the content of bifenthrin as the active ingredient in the technical grade pesticide.

[0007] To address the aforementioned issues, non-patent literature 1 discloses a nano-pesticide prepared by loading bifenthrin onto mesoporous silica. This nano-pesticide can reduce pesticide application while maintaining efficacy, but this preparation method is currently difficult to industrialize.

[0008] Therefore, finding a stable nano-suspension containing bifenthrin and its industrially producible preparation method is crucial for realizing the industrialization of bifenthrin-based nano-pesticides.

[0009] Patent application document 1: CN111418603A, an aqueous suspension containing bifenthrin and flufenoxuron, its preparation method and application;

[0010] Non-patent literature 1: Hu Xin, Xia Hao, Wang Weiyun, et al. Effects of mesoporous silica nanoparticles loaded with bifenthrin on the bioactivity of the tea geometrid moth [J]. Pharmaceutical Biotechnology, 2022, 29(6):7. Summary of the Invention

[0011] 1. The problem to be solved

[0012] One of the objectives of this invention is to provide a nano-suspension containing bifenthrin, given the lack of stable bifenthrin-based nano-suspensions.

[0013] Meanwhile, given the current lack of a method for preparing bifenthrin-containing nano-suspensions that can be industrially produced, a second objective of this invention is to provide a method for preparing bifenthrin-containing nano-suspensions.

[0014] 2. Technical Solution

[0015] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0016] The first aspect of this invention provides a nano-suspending agent containing bifenthrin, comprising:

[0017] Bifenthrin 5-40 parts;

[0018] 10-36 parts of auxiliary agent;

[0019] Add water to make up to 100 servings;

[0020] The bifenthrin has a particle size characteristic of D98≤0.7μm;

[0021] The additives include dispersants, which include cationic polymers and anionic naphthalene sulfonate formaldehyde condensates;

[0022] Based on mass calculations, the amount of the cationic polymer used accounts for less than 15% of the total amount of the nano-suspending agent.

[0023] Based on mass calculation, the ratio of the amount of the ionic naphthalene sulfonate formaldehyde condensate to the amount of the cationic polymer is (0.5-2):(5-12).

[0024] According to any embodiment of the first aspect of the present invention, the amount of the cationic polymer used in the total amount of the nano-suspension agent needs to be greater than 4% and less than 15% by mass.

[0025] According to any embodiment of the first aspect of the present invention, the amount of the cationic polymer used accounts for 5% to 13% of the total amount of the nano-suspending agent, calculated by mass.

[0026] According to any embodiment of the first aspect of the object of the present invention, the cationic polymer has a structure as shown in the following formula:

[0027]

[0028] In the formula:

[0029] R can be any one of -CH2-O-, -CH2CH2-O-, or -OCH2CH2CH2CH2-O-;

[0030] R1 is any one of -H, -CH3, or -CH2CH3;

[0031] R2 is any one of -H, -CH3, or -CH2CH3;

[0032] R3 can be any one of -H, -CH3, or -CH2CH3;

[0033] R4 is -H;

[0034] R5 can be either -H or -CH3;

[0035] R6 is any one of -H, -CH3, or -CH2CH3;

[0036] R7 can be any one of -H, -CH3, or -CH2CH3;

[0037] R8 can be any one of -H, -CH3, or -CH2CH3;

[0038] R9 is a phenyl group;

[0039] R 10 It is a straight-chain or branched, saturated or unsaturated alkyl group having 4 to 21 carbon atoms;

[0040] R 11 It can be either -H or -OOCCH3;

[0041] M can be any one of sodium ion, potassium ion or ammonium ion;

[0042] n1, n2, and n3 are all integers from 0 to 34, and the values ​​of n1, n2, and n3 are all non-zero integers, and the molecular weight of the alkoxy chain containing n1, n2, and n3 is 200 to 1500;

[0043] m is any integer from 1 to 10;

[0044] x is the molar percentage of A and is between 10% and 50%.

[0045] y is the molar percentage of B and is between 10% and 30%.

[0046] z represents the molar percentage of C and ranges from 2% to 80%.

[0047] According to any embodiment of the first aspect of the object of the present invention, the dispersant further includes an auxiliary agent that also includes a phosphate ester salt type anionic surfactant.

[0048] According to any embodiment of the first aspect of the present invention, the ratio of the amount of the ionic naphthalene sulfonate formaldehyde condensate, the amount of the cationic polymer, and the amount of the phosphate ester anionic surfactant, calculated by mass, is (0.5-2):(5-12):1.

[0049] According to any embodiment of the first aspect of the object of the present invention, the additive further includes a wetting agent;

[0050] The wetting agent includes, but is not limited to, any one or two or more of lignin sulfonate, aminosulfonate, and sodium salt of phenol-formaldehyde copolymer.

[0051] According to any embodiment of the first aspect of the present invention, the adjuvant further includes a synergist, which includes, but is not limited to, any one or two of nonionic fatty alcohol ether phosphate, nonionic fatty alcohol polyoxyethylene ether, and polyether-modified trisiloxane.

[0052] According to any embodiment of the first aspect of the object of the present invention, a thickener, including but not limited to any one or two of magnesium aluminum silicate and xanthan gum.

[0053] According to any embodiment of the first aspect of the object of the present invention, the additive further includes an antifoaming agent, which includes, but is not limited to, organosilicon.

[0054] According to any embodiment of the first aspect of the present invention, the additive further includes an antifreeze agent, which includes, but is not limited to, any one or two or more of ethylene glycol, glycerol, and propylene glycol.

[0055] According to any embodiment of the first aspect of the object of the present invention, the additive further includes a preservative, which includes, but is not limited to, sodium benzoate.

[0056] According to any embodiment of the first aspect of the present invention, the additives further include any one, two, three, four, or five of the following: synergists, thickeners, defoamers, antifreeze agents, and preservatives.

[0057] According to any embodiment of the first aspect of the present invention, the addition ratio of the dispersant, wetting agent, synergist, thickener, defoamer, antifreeze agent and preservative is (5-19):(1-5):(0.5-3):(0.5-2):(0.1-1):(2-6):(0-1);

[0058] The preferred ratio is (5-15):(1-2):(1-3):(0.5-1):(0.1-0.5):(3-5):(0.2-0.5).

[0059] A second aspect of this invention provides a method for preparing a nano-suspension containing bifenthrin, comprising the steps of:

[0060] 1) Prepare a first solution containing a dispersant;

[0061] 2) Add bifenthrin to the first solution and disperse it using a high-speed shear mill, then mill it with a sand mill until D90≤10μm to obtain the second solution;

[0062] 3) The second solution is then pulverized using a nano-grinding mill until the particle size D90≤0.5μm and D98≤0.7μm, to obtain the third solution.

[0063] According to any embodiment of the second aspect of the object of the present invention, the first solution further contains a wetting agent.

[0064] According to any embodiment of the second aspect of the object of the present invention, the first solution further contains an antifoaming agent.

[0065] According to any embodiment of the second aspect of the object of the present invention, the second solution further contains an antifoaming agent.

[0066] According to any embodiment of the second aspect of the present invention, the method further includes step 4), adding the synergist to the third solution to obtain the fourth solution.

[0067] According to any embodiment of the second aspect of the present invention, the method further includes step 5), adding the defoamer and thickener to the fourth solution and stirring to obtain the suspension; wherein,

[0068] The defoamer in step 1), the defoamer in step 2), and the defoamer in step 5) are in a mass ratio of (1-3):(1-3):(1-3).

[0069] According to any embodiment of the second aspect of the present invention, the shearing and dispersion time in step 2) is 2 to 10 minutes; the rotation speed is 1000-2000 r / min.

[0070] Beneficial effects

[0071] 1) This invention provides a nanoscale suspension containing bifenthrin, wherein the suspension has a relatively ideal particle size distribution, good particle size stability at room temperature and thermal storage, and good thermal storage stability;

[0072] 2) The nanoscale bifenthrin-containing suspension provided by the present invention includes a dispersant comprising a cationic polymer and an anionic naphthalene sulfonate formaldehyde condensate in its raw materials. The combination of the two can effectively improve the grinding efficiency (referred to as grinding efficiency) of the bifenthrin-containing suspension during the preparation process, as well as the stability of the particle size, storage stability and suspension rate of the prepared bifenthrin-containing suspension. Detailed Implementation

[0073] This disclosure can be more readily understood by referring to the following description in conjunction with examples, all of which form part of this disclosure. It should be understood that this disclosure is not limited to the specific products, methods, conditions, or parameters described and / or shown herein. Furthermore, the terminology used herein is for the purpose of describing particular embodiments by way of example only and is not intended to be limiting, unless otherwise stated.

[0074] It should also be understood that, for clarity, certain features of this disclosure may be described herein in the context of individual embodiments, but may also be provided in combination with each other in individual embodiments. That is, unless obviously incompatible or specifically excluded, each individual embodiment is considered to be combinable with any other embodiment, and such combination is considered to represent another different embodiment. Conversely, for brevity, various features of this disclosure described in the context of individual embodiments may also be provided individually or in any sub-combination. Finally, while a particular embodiment may be described as part of a series of steps or part of a more general structure, each step or substructure may also be considered an independent embodiment in itself.

[0075] Unless otherwise stated, it should be understood that each individual element in the list and each combination of individual elements in the list will be interpreted as a different embodiment. For example, a list of embodiments denoted as "A, B, or C" should be interpreted as including embodiments "A", "B", "C", "A or B", "A or C", "B or C", or "A, B, or C".

[0076] In this disclosure, the singular forms of the articles “a,” “one,” and “the” also include the corresponding plural references, and references to a particular value include at least that particular value, unless the context clearly indicates otherwise. Thus, for example, a reference to “substance” is a reference to at least one of such substance and its equivalents.

[0077] Ordinal terms such as “first” and “second” may be used to describe various components or fluids, but these components and fluids are not limited by these terms. Therefore, without departing from the teachings of this disclosure, these terms are used only to distinguish one component / fluid from another.

[0078] When an item is described using the combined terms “...and / or ...", the description should be understood to include any one of the listed items and all combinations thereof.

[0079] Generally, the use of the term "about" indicates an approximation that can vary depending on the desired characteristics obtained from the disclosed subject matter and will be interpreted in a context-dependent manner based on function. Therefore, those skilled in the art will be able to interpret a degree of difference on a case-by-case basis. In some cases, the number of significant figures used when expressing a particular value can be a representative technique for determining the difference allowed by the term "about." In other cases, a gradient within a range of values ​​can be used to determine the range of differences allowed by the term "about." Furthermore, all ranges in this disclosure are inclusive and composable, and references to values ​​described within a range include every value within that range.

[0080] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terms used herein and / or include any and all combinations of one or more of the associated listed items.

[0081] [1] A nano-suspension containing bifenthrin, wherein the suspension comprises the following raw material components:

[0082] Bifenthrin 5-40 parts;

[0083] 10-36 parts of auxiliary agent;

[0084] Add water to make up to 100 servings;

[0085] Wherein, the "bifenthrin" contained in the suspension can selectively satisfy any one or any combination of the following (I) to (VI); wherein (I) to (VI) are respectively:

[0086] (I) At room temperature, it has a particle size characteristic of D98≤0.7μm;

[0087] (II) At room temperature, it has a particle size characteristic of D90≤0.5μm;

[0088] (III) At room temperature, it has a particle size characteristic of D98≤0.7μm and a particle size characteristic of D90≤0.5μm;

[0089] (Ⅳ) After thermal storage, it has a particle size characteristic of D98≤0.7μm;

[0090] (V) After thermal storage, it has a particle size characteristic of D90≤0.5μm;

[0091] (VI) After thermal storage, it has a particle size characteristic of D98≤0.7μm and a particle size characteristic of D90≤0.5μm;

[0092] The heat storage is performed according to the method in section 2.1 "Liquid Preparations" of GB / T 19136-2003.

[0093] The "auxiliary agent" contained in the suspending agent includes a dispersant. In addition, the "auxiliary agent" may selectively satisfy any one or any combination of the following (I) to (VI); wherein (I) to (VI) are respectively:

[0094] (I) The additives include any one, two, three, four, five or six of the following: wetting agents, synergists, thickeners, defoamers, antifreeze agents and preservatives.

[0095] (II) The addition ratio of the dispersant, wetting agent, synergist, thickener, defoamer, antifreeze and preservative is (5-19): (1-5): (0.5-3): (0.5-2): (0.1-1): (2-6): (0-1).

[0096] The "dispersant" used in this invention needs to satisfy the following conditions: it comprises a cationic polymer and an anionic naphthalenesulfonate formaldehyde condensate, and the amount of the cationic polymer, calculated by mass, accounts for no more than 15% and no less than 3% of the total amount of the suspending agent, preferably 5-12%; for example, the amount of the cationic polymer can be 5.5%, 6%, 7%, 8%, 9%, 10%, 11%, or 12% of the total amount of the suspending agent. In addition, the "dispersant" can selectively satisfy any one or any combination of the following (I) to (II); where (I) to (II) are respectively:

[0097] (I) The dispersant also includes phosphate salt anionic surfactants (or phosphate ester anionic surfactants);

[0098] The “phosphate ester type anionic surfactants” mentioned herein mainly include alkyl (aryl) phosphate esters (salts), fatty alcohol (alkylphenol) polyoxyethylene ether phosphate esters, alkyl alcohol amide phosphate esters (salts), imidazoline phosphate esters (salts), high molecular weight polyphosphate esters (salts), and siloxane phosphate esters, etc.

[0099] (II) The ratio of the amount of the ionic naphthalene sulfonate formaldehyde condensate, the amount of the cationic polymer, and the amount of the phosphate ester anionic surfactant, calculated by mass, is (0.5-2):(5-12):1.

[0100] As a "wetting agent" used in this invention, it includes, but is not limited to, any one or two or more of lignin sulfonate, aminosulfonate, and sodium salt of phenol-formaldehyde copolymer.

[0101] As a "synergist" used in this invention, it includes, but is not limited to, any one or two of nonionic fatty alcohol ether phosphate, nonionic fatty alcohol polyoxyethylene ether, and polyether-modified trisiloxane.

[0102] The "thickening agent" used in this invention includes, but is not limited to, any one or two of magnesium aluminum silicate and xanthan gum.

[0103] As an "antifoaming agent" used in this invention, it includes, but is not limited to, organosilicon.

[0104] As an "antifreeze agent" used in this invention, it includes, but is not limited to, any one or two or more of ethylene glycol, glycerol, and propylene glycol.

[0105] As a "preservative" used in this invention, sodium benzoate is included, but is not limited to.

[0106] As described herein, the cationic polymer, which is one of the components of the dispersant, has the following structural formula:

[0107]

[0108] In the formula:

[0109] R can be any one of -CH2-O-, -CH2CH2-O-, or -OCH2CH2CH2CH2-O-;

[0110] R1 is any one of -H, -CH3, or -CH2CH3;

[0111] R2 is any one of -H, -CH3, or -CH2CH3;

[0112] R3 can be any one of -H, -CH3, or -CH2CH3;

[0113] R4 is -H;

[0114] R5 can be either -H or -CH3;

[0115] R6 is any one of -H, -CH3, or -CH2CH3;

[0116] R7 can be any one of -H, -CH3, or -CH2CH3;

[0117] R8 can be any one of -H, -CH3, or -CH2CH3;

[0118] R9 is a phenyl group;

[0119] R 10 It is a straight-chain or branched, saturated or unsaturated alkyl group having 4 to 21 carbon atoms;

[0120] R 11 It can be either -H or -OOCCH3;

[0121] M can be any one of sodium ion, potassium ion or ammonium ion;

[0122] n1, n2, and n3 are all integers from 0 to 34, and the values ​​of n1, n2, and n3 are all non-zero integers, and the molecular weight of the alkoxy chain containing n1, n2, and n3 is 200 to 1500;

[0123] m is any integer from 1 to 10;

[0124] x is the molar percentage of A and is between 10% and 50%;

[0125] y is the molar percentage of B and is between 10% and 30%.

[0126] z represents the molar percentage of C and ranges from 2% to 80%.

[0127] It has the "cationic polymer" with the structural formula shown above, and one method for its preparation is as follows:

[0128] 1) Add reactant A, reactant C, and chain transfer agent to a solvent prepared from double-distilled water and isopropanol, stir, and heat under reflux to obtain a mixed solution; add reactant B and initiator solution dropwise to the mixed solution; or

[0129] The reactants and chain transfer agents are mixed and added to a solution prepared with double-distilled water and isopropanol in a certain proportion. The mixture is stirred and heated under reflux to obtain a mixed solution. Reactants B, C, and an initiator solution are then added dropwise to the mixed solution obtained in step [1].

[0130] The reactant C and chain transfer agent are mixed and added to a solution prepared by double distilled water and isopropanol in a certain proportion. The mixture is stirred and heated under reflux to obtain a mixed solution. Reactant A, reactant B and initiator solution are added dropwise to the mixed solution obtained in step 1.

[0131] The reaction monomer A is one of the following: an alkoxylated product of allyl alcohol, an alkoxylated product of methyl allyl alcohol, an alkoxylated product of isopentenol, an alkoxylated product of 4-hydroxybutyl vinyl ether, or an acetate derivative thereof.

[0132] The heating temperature is 60–90°C; the dripping time is 1–4 hours.

[0133] The chain transfer agent is one or more of 3-mercaptopropionic acid, mercaptoacetic acid, mercaptoethanol, isopropanol, dodecyl mercaptan, and octanol;

[0134] The initiator is one or more of the following combinations: ammonium persulfate and sodium bisulfite, potassium persulfate and sodium bisulfite, or ammonium persulfate and ferrous sulfate.

[0135] The reactive monomer B is styrene;

[0136] The reaction monomer C is maleic anhydride monoesterified ethoxylated vegetable oil amine;

[0137] The mass ratio of the three reactive monomers A, B, and C is (1-5):(1-3):(2-8);

[0138] The mass concentration of isopropanol in the solution prepared by double-distilled water and isopropanol is 20-45%.

[0139] The total mass of the monomers is the sum of the masses of reactant monomers A, B, and C. The amount of chain transfer agent is 0.5-10% of the total mass of the monomers; the amount of initiator is 2-16% of the total mass of the monomers.

[0140] 2) After the addition is complete, continue to keep the temperature at 60-90℃ and reflux for 2-6 hours. Then, use one or more of sodium hydroxide, potassium hydroxide, ethanolamine, triethanolamine or ammonia water in any proportion to adjust the pH to 7.5-10.5.

[0141] 3) Chloromethane is introduced at 70–80°C to quaternize the tertiary amine group.

[0142] [2] A method for manufacturing nano-suspensions containing bifenthrin, comprising steps 1) to 3):

[0143] 1) Prepare a first solution containing a dispersant;

[0144] 2) Add bifenthrin to the first solution and disperse it using a high-speed shear mill, then mill it with a sand mill until D90≤10μm to obtain the second solution;

[0145] 3) The second solution is then pulverized using a nano-grinding mill until the particle size D90≤0.5μm and D98≤0.7μm, to obtain the third solution.

[0146] Preferably, it also includes step 4), or steps 4) and 5):

[0147] 4) Add the synergist to the third solution to obtain the fourth solution;

[0148] 5) Add the defoamer and thickener to the fourth solution and stir to obtain the suspension.

[0149] As described in step 1): Prepare a first solution, the first solution containing a dispersant;

[0150] The typical operating procedure for this step 1) is as follows: dissolve the dispersant in water to obtain the first solution;

[0151] In addition, the "first solution" may selectively satisfy any one or any combination of the following (I) to (VI); wherein (I) to (II) are respectively:

[0152] (I) The first solution also contains a wetting agent;

[0153] (II) The first solution also contains an antifreeze agent;

[0154] (III) The first solution also contains an antifoaming agent.

[0155] As in step 2): Bifenthrin is added to the first solution and sheared and dispersed using a high-speed shear mill, and then milled with a sand mill until D90≤10μm to obtain the second solution;

[0156] In addition, in "step 2)," bifenthrin and defoamer can be added to the first solution at the same time before proceeding with the subsequent shearing and grinding.

[0157] As described in steps 1) to 5): the total addition ratio of dispersant, wetting agent, synergist, thickener, defoamer, antifreeze and preservative is (5-19): (1-5): (0.5-3): (0.5-2): (0.1-1): (2-6): (0-1).

[0158] The defoamer in step 1), the defoamer in step 2), and the defoamer in step 5) are in a mass ratio of (1-3):(1-3):(1-3).

[0159] In the following examples, the cationic polymer used has the following formula:

[0160]

[0161] Its preparation method is as follows:

[0162] Take allyl alcohol alkoxy compounds (n1=5, n2=8, n3=10, R1, R3, R 11 10g of maleic anhydride monoesterified ethoxylated coconut oil amine (m=1, R ... 10 C 12 H 23 80g of styrene, 510g of a double-distilled aqueous solution of isopropanol (isopropanol content 25%), and 6g of dodecyl mercaptan were added to a reaction vessel, stirred, and heated to about 75-80℃ and kept at that temperature for 0.5-1 hour. Within 2.5 hours, 10g of styrene and 10g of potassium persulfate / sodium bisulfite initiator were added dropwise to the above solution, and the reaction was kept at that temperature for 4 hours. Then, NaOH, a pH adjuster, was added to the reaction vessel to adjust the pH to 7.9. Finally, 11g of chloromethane was introduced at 70-80℃, and the reaction was kept at 75-80℃ for 1.5-2 hours to remove isopropanol. The cationic polymer used in the following examples was obtained.

[0163] The following table shows some of the reagents used in the examples, along with their names and available purchase channels:

[0164]

[0165] The present invention will be further illustrated below with reference to specific embodiments, but these embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field. The essential features and significant effects of the present invention can be seen from the following embodiments. The described embodiments are some, but not all, embodiments of the present invention, and therefore do not limit the present invention in any way. Any non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are within the protection scope of the present invention. Specific Implementation

[0167] 1. Preparation of suspending agents

[0168] The following Examples 1-5 or Comparative Examples 1-6 were prepared according to the following steps to obtain nano-suspensions containing bifenthrin. The raw materials and formulations used are shown in Tables 1 and 2:

[0169] 1) Take some water and all the xanthan gum to prepare a 2wt% xanthan gum solution.

[0170] 2) Dissolve the dispersant, wetting agent, antifreeze, and part of the defoamer in the remaining water to obtain the first solution;

[0171] 3) Add bifenthrin and part of the defoamer to the first solution and shear and disperse them using a high-speed shear mill, then grind them with a sand mill until D90≤10μm to obtain the second solution;

[0172] The shearing and dispersion time is 2 minutes.

[0173] The rotational speed for shear dispersion is 2000 r / min.

[0174] 4) The second solution is then milled using a nano-grinding mill until the particle size D90≤0.5μm and D98≤0.7μm, to obtain the third solution;

[0175] 5) Add the synergist to the third solution and stir until homogeneous to obtain the fourth solution;

[0176] 6) Add the remaining defoamer and thickener (magnesium aluminum silicate, 2 wt% xanthan gum solution) to the fourth solution and stir and disperse using a stirrer to obtain the suspension.

[0177] The defoamer in step 1), the defoamer in step 2), and the defoamer in step 5) have a mass ratio of 1:1:2.

[0178] Table 1. Formulations of nano-suspension agents containing bifenthrin in Examples 1-5

[0179]

[0180] Table 2. Comparative Examples 1-5: Nano-suspensions containing bifenthrin

[0181]

[0182] 2. Dispersion performance and interface performance verification

[0183] The processing efficiency (in min), initial particle size (in μm) at the end of grinding, particle size at room temperature (in μm), thermal storage particle size (in μm), thermal storage water separation rate (in %), room temperature suspension rate (in %), thermal storage suspension rate (in %), surface tension (in mN / m), thermal storage decomposition rate (in %), and penetration time of the nano-suspension agents containing bifenthrin in Examples 1-5 and Comparative Examples 1-5 were measured respectively. The results are shown in Table 3.

[0184] Viscosity (unit: MPa) was measured using a digital rotational viscometer with rotor No. 3 selected and the viscosity of the sample measured at 60 rpm.

[0185] Samples stored at room temperature for 2 months and heat-stored for 14 days were measured using a Malvern laser particle size analyzer Mastersizer 3000. The measurements were performed in triplicate and the average value was taken.

[0186] Low-temperature stability shall be performed in accordance with section 2.2 "Suspension Formulations" of GB / T 19137-2003;

[0187] Thermal storage stability shall be performed in accordance with the method of 2.1 "Liquid Formulations" in GB / T 19136-2003;

[0188] The suspension rate was determined in accordance with section 4.4 of GB / T 14825—2006;

[0189] Surface tension was measured using the platinum plate method.

[0190] Table 3. Performance of nano-suspensions containing bifenthrin

[0191]

[0192] From Table 3 combined with Tables 1 and 2, we can see that:

[0193] 1) Grinding efficiency: A comparison of Examples 1-5 of the present invention with Comparative Examples 1 and 2 shows that the groups of Examples 1-5 of the present invention have significantly superior grinding efficiency, indicating that the combination of SP-2 and dispersant NNO can effectively improve the grinding efficiency in the preparation process of suspension. It was found that SP-2 can penetrate into the cracks of small particles caused by compression and collision after the pesticide particles are mechanically ground, preventing the broken pesticide particles from re-aggregating due to their hydrophobicity. The combination of the two can effectively improve the grinding efficiency.

[0194] Furthermore, a comparison of Examples 1-5 of the present invention shows that Examples 4 and 5 are dispersant groups containing phosphate ester salt type anionic surfactants, which have relatively better grinding efficiency, and the grinding efficiency is not reduced by the increase of bifenthrin content.

[0195] 2) Initial particle size: Compared with Comparative Examples 1 and 2, the suspensions obtained after preparation from the raw materials of Examples 1-5 of the present invention have smaller and more uniform particle sizes, indicating that the synergistic effect of SP-2 and dispersant NNO can ensure a more uniform particle size distribution after sand milling (Examples 1-5). However, in Comparative Examples 1 or 2, it can be found that even when milled to the same D90 level, there is still a large D98. The presence of particles with this smaller particle size will have an adverse effect on subsequent storage stability.

[0196] 3) Thermal storage particle size: Compared with Comparative Examples 1 and 2, the suspending agents obtained after preparation from the raw materials of Examples 1-5 of the present invention exhibit smaller changes in thermal storage particle size. After thermal storage, the particle size D90 is ≤0.5μm and D98 is ≤0.7μm, while the suspension rate at room temperature reaches over 99% and the suspension rate at thermal storage reaches over 98.5%. In contrast, the particle size increase after thermal storage in Comparative Examples 1-2 is relatively large, and the suspension rates at both room temperature and thermal storage are below 98%.

[0197] Research revealed that the SP-2 macromolecular chain provides sterically hindered hydrophobic segments—containing benzene rings or benzene ring-like groups—with dispersion forces and hydrogen bonding between them and pesticide particles, providing multiple anchoring sites to firmly adhere to the surface of the adsorbed pesticide particles; hydrophilic segments—alkoxy solvation chains—enhance the dispersion ability of the adsorbed pesticide particles in water; nitrogen-containing cations provide electrostatic repulsion; and the synergistic effect with the adsorption capacity of the dispersant NNO ensures that the dispersant remains firmly adsorbed on the particle surface even under temperature changes, with minimal change in thermal storage particle size.

[0198] 4) Effect of synergists: Compared with Comparative Example 3, the suspensions obtained from the raw materials of Examples 1-5 of this invention exhibit better particle size retention, better dispersion stability, higher suspension rate, and no water separation problem during thermal storage. This indicates that the synergists fatty alcohol ether phosphate MOA-3P and fatty alcohol polyoxyethylene ether AEO-9 have a more suitable surface tension regulation, and the combination of dispersant SP-2 and dispersant NNO shows better compatibility.

[0199] 5) Comparative Example 4 found that the amount of dispersant SP-2 should not exceed 15% because excessive additives have a lubricating effect on the grinding beads, which reduces the grinding efficiency; the remaining dispersant occupies the suspension system, causing the original drug particles to be unable to maintain a safe distance and to be adsorbed and brought closer together again, eventually resulting in aggregation, flocculation, and particle size increase.

[0200] 3. Verification of prevention and control effects

[0201] 1) Target pests: Pear psyllids, young nymphal stages

[0202] 2) Experimental design: The experiment set up 16 treatments, each with a plot area of ​​60 square meters, with 3 replicates, for a total of 48 plots, arranged in a randomized block design. The application of the agent for each treatment is shown in Table 4.

[0203] Table 4. Test reagents and dosages

[0204]

[0205] 4) Survey methods:

[0206] Three trees were surveyed in each area, with five infested shoots on each tree marked with tags. The number of live pear psyllids on the leaves was then counted. The initial pear psyllid population was surveyed before application, and the number of surviving live pear psyllids was surveyed at 1, 3, 7, and 10 days after application, for a total of four surveys. The control efficacy was calculated using the following formula:

[0207] Insect population reduction rate (%) = (number of live insects before treatment - number of live insects after treatment) / number of live insects before treatment × 100;

[0208] Corrected control efficacy (%) = (Pest population reduction rate in the treated area - Pest population reduction rate in the control area) / (1 - Pest population reduction rate in the control area) × 100

[0209] The specific prevention and control effects are shown in Table 5.

[0210] Table 5. Control efficacy results

[0211]

[0212]

[0213] As can be seen from Table 5 above:

[0214] 1) All treatments are safe for pear trees and do not cause any phytotoxicity.

[0215] 2) Under the same dosage, the control effect of the suspension in Example 4 is significantly better than that of other comparative suspensions and commercially available products, indicating that the formulation composition and ratio of Example 4 are better, the particle size distribution is more uniform, and the deposition effect on the target surface is better.

[0216] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A nano-suspension containing bifenthrin, characterized in that, include Bifenthrin 5-40 parts; 10-36 parts of auxiliary agent; Add water to make up to 100 servings; The bifenthrin has a particle size characteristic of D98≤0.7μm; The additives include dispersants, wetting agents, synergists, thickeners, defoamers, antifreeze agents, and preservatives. The addition ratio of the dispersants, wetting agents, synergists, thickeners, defoamers, antifreeze agents, and preservatives is (5~19):(1~5):(0.5~3):(0.5~2):(0.1~1):(2~6):(0~1). The synergist is selected from any one or more of nonionic fatty alcohol ether phosphate, nonionic fatty alcohol polyoxyethylene ether, and polyether-modified trisiloxane; The dispersant comprises a cationic polymer and an anionic naphthalene sulfonate formaldehyde condensate; by mass, the amount of the cationic polymer accounts for more than 4% and less than 15% of the total amount of the nano-suspending agent. Based on mass calculations, the ratio of the amount of the anionic naphthalene sulfonate formaldehyde condensate to the amount of the cationic polymer is (0.5~2):(5~12). The cationic polymer has the structure shown in the following formula: In the formula: R can be any one of -CH2-O-, -CH2CH2-O-, or -OCH2CH2CH2CH2-O-; R1 is any one of H, -CH3, or -CH2CH3; R2 is any one of H, -CH3, or -CH2CH3; R3 is any one of H, -CH3, or -CH2CH3; R4 is H; R5 can be either H or -CH3; R6, R7, and R8 are H; R9 is a phenyl group; R 10 It is a straight-chain or branched, saturated or unsaturated alkyl group having 4 to 21 carbon atoms; R 11 For H; M can be any one of sodium ion, potassium ion or ammonium ion; n1, n2, and n3 are all any integers from 0 to 34, and the values ​​of n1, n2, and n3 are non-zero integers. The molecular weight of the alkoxy chain containing n1, n2, and n3 is 200 to 1500. m is any integer from 1 to 10; x represents the molar percentage of reactant monomer A and is between 10% and 50%. y represents the molar percentage of reactant monomer B and is between 10% and 30%. z represents the molar percentage of the reactant monomer C and ranges from 2% to 80%. The reaction monomer A is any one or more of the alkoxylated products of allyl alcohol, the alkoxylated products of methyl allyl alcohol, the alkoxylated products of isopentenol, and the alkoxylated products of 4-hydroxybutyl vinyl ether. The reactive monomer B is styrene; The reactant monomer C is maleic anhydride monoesterified ethoxylated vegetable oil-based amine.

2. The nano-suspension containing bifenthrin according to claim 1, characterized in that, The dispersant also includes phosphate ester salt type anionic surfactants; Based on mass calculations, the ratio of the amount of the anionic naphthalene sulfonate formaldehyde condensate, the amount of the cationic polymer, and the amount of the phosphate ester anionic surfactant is (0.5~2):(5~12):

1.

3. The nano-suspension containing bifenthrin according to any one of claims 1 to 2, characterized in that, The wetting agent includes any one or two or more of lignin sulfonate, aminosulfonate, and sodium salt of phenol-formaldehyde copolymer.

4. The nano-suspension containing bifenthrin according to claim 3, characterized in that, The thickener includes any one or two of magnesium aluminum silicate and xanthan gum; and / or, The defoamer includes organosilicon; and / or, The antifreeze includes any one or more of ethylene glycol, glycerol, and propylene glycol; and / or, The preservative includes sodium benzoate.

5. A method for preparing a nano-suspension containing bifenthrin as described in any one of claims 1 to 4, characterized in that, Including the following steps: 1) Prepare a first solution containing a dispersant, a wetting agent, a defoamer, and an antifreeze. 2) Add bifenthrin to the first solution and shear it using a high-speed shear mill, then mill it with a sand mill until D90≤10μm to obtain the second solution, which contains an antifoaming agent; 3) The second solution is then pulverized using a nano-grinding mill until the particle size D90≤0.5μm and D98≤0.7μm, to obtain the third solution; 4) Add the synergist to the third solution to obtain the fourth solution; 5) Add the defoamer and thickener to the fourth solution and stir to obtain the suspension; in, The defoamer in step 1), the defoamer in step 2), and the defoamer in step 5) are in a mass ratio of (1~3):(1~3):(1~3).

6. The method for preparing the nano-suspension containing bifenthrin according to claim 5, characterized in that, The shear dispersion time in step 2) is 2~10 min; The rotational speed is 1000-2000 r / min.

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