Dispersing agent composition and application thereof

Abstract

The invention discloses a dispersant composition and application thereof, and belongs to the technical field of pesticide adjuvants. The dispersant composition provided by the invention comprises a weak cationic polycarboxylate and an anionic dispersant, the anionic dispersant comprises one or more of polynaphthalene sulfonate, polycarboxylate, lignosulfonate and phosphate ester salt. The dispersant composition provided by the invention can effectively regulate and control the particle size of pesticide particles and improve the stability of a dispersion system.

Description

Technical Field

[0001] The present invention relates to the technical field of pesticide adjuvants, and more specifically to a dispersant composition and application thereof. Background Art

[0002] In the field of pesticide formulations, suspension concentrate (SC) is an important dosage form, and its particle size distribution directly affects the stability and use effect of the product. However, in the actual production process, some suspension formulations of pesticides, such as 8% flufenacet + 24% flufenacet suspension, often face the problem of large particle size and uneven dispersion, which not only affects the suspension stability and spraying uniformity of the pesticide, but also reduces the bioavailability and control effect of the pesticide.

[0003] Currently, the most commonly used adjuvant structures reported in SC formulations are polycarboxylates and naphthalenesulfonates with anionic properties. Although polycarboxylates and naphthalenesulfonates with anionic properties can improve the dispersibility of suspensions to a certain extent, there are always deficiencies in particle size control. For example, in high-concentration or complex systems, the dispersing effect of naphthalenesulfonates is easily affected, resulting in uneven particle size distribution, and the growth of particle size cannot be well controlled, making it difficult to meet the market demand for high-quality pesticide formulations. In addition, the sensitivity of polycarboxylates and naphthalenesulfonate dispersants with anionic properties to environmental factors such as ionic strength of the suspension dispersion system also affects the stability of their dispersing effect. For example, a large amount of calcium and magnesium ions in hard water are easily combined with carboxylates and sulfonates on the surface of the dispersant in the water suspension, thereby causing precipitation of the water-suspended particles of the pesticide and reducing the suspension rate of the water-suspended particles of the pesticide in the water body.

[0004] In the prior art, polycarboxylic acid dispersants with cationic properties have the high efficiency and stability of traditional high molecular weight polycarboxylates, and the cations are more tightly encapsulated with the original drug, which has better particle size control growth for preparations with easy particle size growth, such as pyraclostrobin SC and thiazin SC. There are also a large number of patent literature reports on polycarboxylic acid dispersants with cationic properties. For example, the synthesis of a comb-type cationic polymer dispersant disclosed in the Chinese patent with publication number CN118562070A provides a comb-type polymer dispersant with a quaternary ammonium salt type cationic group to stabilize the dispersion of the product. Another example is the synthesis and application of an innovative cationic polycarboxylate high efficiency wetting dispersant disclosed in the Chinese patent with publication number CN118955785A, which also provides a polycarboxylate dispersant containing a quaternary ammonium salt type cationic group to improve the dispersion stability of the system.

[0005] But cationic dispersants also have limitations in the application of pesticide aqueous suspensions, wherein the molecular structure of cationic dispersants carries a positive charge, and is easily combined with anionic substances in water to form precipitation, and cannot be well compatible with anionic dispersants, which limits its compatibility with anionic dispersants, improves the dispersion stability of suspensions and regulates the particle size. But, some patent documents also report the use of cationic dispersants and anions. For example, the Chinese patent publication number CN117296840A discloses a kind of auxiliary agent composition and application thereof, and the dispersant in the auxiliary agent composition provided comprises cationic macromolecular polymer and anionic naphthalenesulfonate formaldehyde condensate, wherein the cationic macromolecular polymer is a polycarboxylate dispersant containing quaternary ammonium salt type cationic group, to realize the preparation of nano suspension, and can make the prepared nano suspension have good stability. But, because the polycarboxylate dispersant contains quaternary ammonium salt type cationic group, it is easy to combine with anionic substances to generate precipitation, affecting the dispersion stability of suspension.

[0006] Therefore, there is an urgent need for a dispersant composition that can effectively control the particle size of pesticide particles in a suspending agent and improve the stability of the dispersion system. Summary of the invention

[0007] 1. Technical problem to be solved by the invention

[0008] In view of the shortcomings of the prior art that the dispersant composition has poor effect on regulating the particle size of pesticide particles in the suspension and the stability of the dispersion system, a dispersant composition is provided, which can effectively regulate the particle size of pesticide particles and improve the stability of the dispersion system.

[0009] 2. Technical solution

[0010] In order to achieve the above object, the technical solution provided by the present invention is:

[0011] A weak cationic polycarboxylate of the present invention has a structure shown in the following formula:

[0012]

[0013] Where:

[0014] R is any one, two or three of -CH2-O-, -CH2 CH2-O-, -OCH2 CH2 CH2 CH2-O-;

[0015] R1 is any one, two or three of -H, -CH3, -CH2 CH3;

[0016] R2 is any one, two or three of -H, -CH3, -CH2 CH3;

[0017] R3 is any one, two or three of -H, -CH3, -CH2 CH3;

[0018] R4 is -H;

[0019] R5 is any one or both of -H and -CH3;

[0020] R6 is any one, two or three of -H, -CH3, -CH2 CH3;

[0021] R7 is any one, two or three of -H, -CH3, -CH2 CH3;

[0022] R8 is any one, two or three of -H, -CH3, -CH2 CH3;

[0023] R9 is phenyl, -CONH2, -C4H6NO, -CH2 O(C2 H4 O) a (C3 H6 O) b H.COOR 3 Any one, two or more of; wherein a is any integer from 1 to 50, b is any integer from 0 to 50, R 3 Any one, two or more of sodium ion, potassium ion or ammonium ion, C1-C20 alkyl group, aralkyl group, and polyoxyethylene oxypropylene chain;

[0024] R 10 Any one or two of -H, -OOCCH3;

[0025] R 11 is any one or two of -H, -COOM; wherein M is any one, two or more of sodium ion, potassium ion or ammonium ion;

[0026] R 12 Any one or two of -H, -CH3;

[0027] R 13 Any one or both of the following structures

[0028]

[0029] Among them, R 14 is any one or two of H, a linear or branched, saturated or unsaturated alkyl group having 1 to 21 carbon atoms; R 15 is any one or two of H, a linear or branched, saturated or unsaturated alkyl group having 1 to 21 carbon atoms; X is any one of nitrogen or oxygen;

[0030] n1, n2, n3 are all integers between 1 and 34;

[0031] n4, n5, n6 are all integers between 0 and 10;

[0032] n is the weight percentage of monomer A and is 10 to 40%;

[0033] m is the weight percentage of monomer B and is 10 to 40%;

[0034] q is the weight percentage of monomer C and is 20 to 60%.

[0035] Preferably, n4, n5, and n6 are all integers between 0 and 5.

[0036] The present invention also provides a method for preparing the above-mentioned weak cationic polycarboxylate, comprising the following steps:

[0037] S1, adding reaction monomer A, reaction monomer C, and chain transfer agent into an isopropanol aqueous solution, stirring and heating under reflux to obtain a mixed solution; and dropwise adding reaction monomer B and initiator solution into the mixed solution;

[0038] S2. After the addition is completed, the mixture is kept warm and refluxed, and then the pH is adjusted to alkaline;

[0039] S3, performing oxidative amination reaction;

[0040] Wherein, in step S1, the reaction monomer A is one of an alkoxylate of allyl alcohol, an alkoxylate of methyl allyl alcohol, an alkoxylate of isopentenol, an alkoxylate of 4-hydroxybutyl vinyl ether or an acetate derivative thereof;

[0041] The reactive monomer B is one of styrene, acrylic acid, methyl methacrylate, methyl acrylate, methyl styrene, allyl polyether, polyethylene glycol monoacrylate, and polyoxyethylene acrylic acid ether;

[0042] The reactive monomer C is one of a derivative of an alkylamino polyether and an acrylate, a derivative of an alkylamino polyether and a maleic anhydride ester, an amide derivative of an alkylamino polyether and acrylic acid, or vinyl pyrrolidone.

[0043] The preparation method can be used to prepare a weakly cationic polycarboxylate with better controlled molecular weight and distribution of the product.

[0044] Further, the derivative of the alkylamino polyether and maleic anhydride ester is

[0045] One of them.

[0046] Further, the alkoxylate of allyl alcohol is One of them.

[0047] Furthermore, in step S1, the mass concentration of isopropanol in the isopropanol aqueous solution is 20-35%.

[0048] Furthermore, in step S1, the mass ratio of the reaction monomer A, the reaction monomer B, and the reaction monomer C is (1-4):(1-4):(2-6).

[0049] Furthermore, in step S1, the heating temperature is 60-90°C.

[0050] Furthermore, in step S1, the dripping time is 1 to 4 hours.

[0051] Furthermore, in step S1, the amount of the chain transfer agent used is 0.5% to 10% of the sum of the amounts of the reaction monomer A, the reaction monomer B and the reaction monomer C, calculated by mass.

[0052] Furthermore, the chain transfer agent is one or more of dicarboxymethyl trithiocarbonate, dibenzyl trithiocarbonate, dicarboxyisopropyl trithiocarbonate, 3-mercaptopropionic acid, thioglycolic acid, mercaptoethanol, isopropanol, dodecyl mercaptan and octanol.

[0053] Furthermore, in step S1, the amount of the initiator used is 2% to 16% of the sum of the amounts of the reaction monomer A, the reaction monomer B and the reaction monomer C, calculated by mass.

[0054] Furthermore, the initiator is one or more of a combination of ammonium persulfate and sodium bisulfite, a combination of potassium persulfate and sodium bisulfite, or a combination of ammonium persulfate.

[0055] Furthermore, in step S2, the insulation temperature is 60-90° C. and the time is 2-6 hours.

[0056] Furthermore, in step S2, the pH is adjusted to 7.5-10.5.

[0057] Furthermore, the pH value can be adjusted by mixing one or more of sodium hydroxide, potassium hydroxide, ethanolamine, triethanolamine or ammonia water in any proportion.

[0058] Furthermore, in step S3, the oxidative amination reaction comprises: adding 22-28% hydrogen peroxide at 70-80° C. to carry out an oxidation reaction on the tertiary amine group, and continuing to keep the temperature at 75-80° C. for 3.5-4 hours.

[0059] Furthermore, the hydrogen peroxide is added in excess.

[0060] The present invention also provides an application of the weak cationic polycarboxylate for preparing a pesticide suspension.

[0061] The present invention also provides a dispersant composition,

[0062] The dispersant composition comprises a weak cationic polycarboxylate and an anionic dispersant;

[0063] The anionic dispersant includes one or more of polynaphthalene sulfonate, polycarboxylate, lignin sulfonate and phosphate.

[0064] Furthermore, the weak cationic polycarboxylate is the above-mentioned weak cationic polycarboxylate or a weak cationic polycarboxylate prepared by the above-mentioned method for preparing the weak cationic polycarboxylate.

[0065] Further, the polynaphthalenesulfonate includes one or more of polynaphthalenesulfonate sodium salt, polynaphthalenesulfonate potassium salt or polynaphthalenesulfonate ammonium salt;

[0066] The polycarboxylate includes one or more of polycarboxylate sodium salt, polycarboxylate potassium salt or polycarboxylate ammonium salt;

[0067] The lignin sulfonate includes one or more of sodium lignin sulfonate, potassium lignin sulfonate or ammonium lignin sulfonate;

[0068] The phosphate includes one or more of sodium phosphate, potassium phosphate or ammonium phosphate.

[0069] Preferably, the anionic dispersant is Meadwestvaco's lignin sulfonate REAX 85A, AkzoNobel's naphthalene sulfonate Morwet D425, Huntsman's polycarboxylate Tersperse 2500, Jiangsu Qingyu Chemical Technology Co., Ltd.'s polycarboxylates SP-27001, SP-DF2238, SP-DF2222, SP-2728, SP-2818L, and Japan Takemoto Oil's YUS-FS3000 phosphate.

[0070] Furthermore, calculated by mass, the mass of the weak cationic polycarboxylate accounts for 50% to 100% of the mass of the dispersant composition, but is not 100%.

[0071] Specifically, calculated by mass, the mass of the weak cationic polycarboxylate may account for 50% to 90% of the mass of the dispersant composition, and the mass of the anionic dispersant may account for 10% to 50% of the mass of the dispersant composition.

[0072] The present invention also provides a method for preparing the above dispersant composition, comprising the following steps:

[0073] The weak cationic polycarboxylate and the anionic dispersant are uniformly mixed to obtain a dispersant.

[0074] Furthermore, the uniform mixing can be performed by stirring.

[0075] Furthermore, the stirring temperature is 20-40°C.

[0076] Preferably, the stirring temperature is room temperature.

[0077] Furthermore, the stirring time may be ≥30 min, preferably 30 min.

[0078] Furthermore, the weak cationic polycarboxylate and the anionic dispersant are mixed uniformly by stirring and mixing a solution containing the weak cationic polycarboxylate and the anionic dispersant.

[0079] The present invention also provides an application of the dispersant composition for preparing a pesticide suspension.

[0080] Furthermore, calculated by mass, the amount of the dispersant composition used accounts for 1% to 6% of the total amount of the suspending agent.

[0081] Preferably, calculated by mass, the amount of the dispersant composition accounts for 5% of the total amount of the suspending agent.

[0082] Furthermore, the suspension comprises an effective ingredient, and the effective ingredient contains one or more of nitrogen, oxygen and phosphorus elements.

[0083] 3. Beneficial effects

[0084] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0085] (1) The weak cationic polycarboxylate provided by the present invention contains a nitrogen oxide structure, i.e., an N→O structure, and has weak cationic properties, which is conducive to compounding with anionic dispersants; and can also improve the stability of the dispersion system and effectively control the particle size through the combined effects of long carbon chains, multiple active adsorption sites, spatial repulsion, and steric hindrance.

[0086] (2) The dispersant composition provided by the present invention comprises a weak cationic polycarboxylate containing a nitrogen oxide structure and an anionic dispersant. The weak cationic polycarboxylate containing a nitrogen oxide structure, i.e., a N→O structure, exhibits good dispersibility in a suspension system due to the combined effects of its long carbon chain, multiple active adsorption sites, spatial repulsion, and steric hindrance; and can also make the entire system exhibit weak cationic characteristics through nitrogen oxidation. Since most pesticide molecules contain nitrogen, oxygen, and phosphorus elements, they will exhibit a certain electronegativity. The weak cationic part in the composition is strongly adsorbed with the anionic groups on the surface of the pesticide molecules, which not only increases the adsorption amount, but also forms a positively charged adsorption layer. The adsorption layer not only changes the charge properties of the particle surface, but also significantly improves the stability of the dispersion system through electrostatic repulsion and steric hindrance effects, thereby achieving precise control of the particle size.

[0087] On the other hand, since the weak cationic properties brought about by the nitrogen oxide structure of the weak cationic polycarboxylate are avoided, the disadvantage that the anions in the cations and anionic dispersants are incompatible can be avoided. The weak cationic polycarboxylates can be compounded and used in combination with the anionic dispersants to make the weak cationic polycarboxylates and the anionic dispersants work at the same time. Different combination ratios can also be adjusted to give full play to the synergistic effect, better stabilize the water suspension dispersion system and control the particle size, and well solve the problem that some single cationic dispersants or single anionic dispersants cannot stabilize and control the particle size.

[0088] (3) The dispersant composition provided by the present invention can also be used in combination with a wetting agent to further reduce viscosity and improve dispersion stability.

[0089] (4) In the preparation method of the dispersant composition provided by the present invention, the weak cationic polycarboxylate containing a nitrogen oxide structure is added dropwise by an initiator and a reaction monomer during the preparation process, thereby ensuring a high reaction conversion rate of the monomer; the addition of a chain transfer agent can obtain a dispersant product with a uniform molecular weight, which exhibits good dispersibility and stability when applied to a water suspension formulation. The preparation process solvent is recyclable, and the synthesis is carried out in the same reactor, without separation in the middle, and without environmental pollution; the process is simple, easy to operate, short production cycle, and suitable for industrial-scale production.

[0090] (5) When the dispersant composition provided by the present invention is used to prepare a suspension, the dispersion system of the suspension prepared is more stable and the particle size is better controlled. DETAILED DESCRIPTION

[0091] The present disclosure may be more easily understood by reference to the following description in conjunction with examples, all of which constitute a part of the present disclosure. It should be understood that the present disclosure is not limited to the specific products, methods, conditions or parameters described and / or illustrated herein. Further, the terms used herein are only used for the purpose of describing specific embodiments by way of example and are not intended to be limiting unless otherwise indicated.

[0092] It should also be understood that, for the sake of clarity, certain features of the present disclosure may be described herein in the context of separate embodiments, but may also be provided in combination with each other in a single embodiment. That is, unless clearly incompatible or specifically not included, each separate embodiment is considered to be combinable with any other embodiment, and the combination is considered to represent another different embodiment. Conversely, for the sake of simplicity, the various features of the present disclosure described in the context of a single embodiment may also be provided individually or in any sub-combination. Finally, although a particular embodiment may be described as part of a series of steps or part of a more general structure, each step or substructure itself may also be considered to be an independent embodiment.

[0093] Unless otherwise indicated, it should be understood that each individual element in a list and each combination of individual elements in the list will be interpreted as a different embodiment. For example, a list of embodiments represented as "A, B, or C" should be interpreted to include embodiments "A", "B", "C", "A or B", "A or C", "B or C", or "A, B, or C".

[0094] In the present disclosure, the singular forms of the articles "a," "an," and "the" also include the corresponding plural references, and a reference to a specific value includes at least that specific value unless the context clearly indicates otherwise. Thus, for example, a reference to "a substance" is a reference to at least one of that substance and equivalents thereof.

[0095] When items are described by using the conjunction terms "... and / or...," etc., the description should be understood to include any one of the associated listed items and all combinations of one or more thereof.

[0096] In general, the use of the term "about" indicates an approximate value that can vary depending on the desired properties obtained by the disclosed subject matter, and will be interpreted in a context-dependent manner based on function. Therefore, one of ordinary skill in the art will be able to interpret a certain 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 in a range of values ​​can be used to determine the range of differences allowed by the term "about". Further, all ranges in this disclosure are inclusive and combinable, and reference to a value in a range includes each value within that range.

[0097] 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 the invention belongs; the terms used herein and / or include any and all combinations of one or more of the associated listed items.

[0098] In the following 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 purchased commercially.

[0099] Jiangsu Qingyu Technology Co., Ltd.'s products include polynaphthalene sulfonate SP-2818L, SP-2728, SP-DF2238, SP-27001; Meadwestvaco's lignin sulfonate REAX 85A; Huntsman's polycarboxylate Tersperse 2500; Japan Takemoto Oil's YUS-FS3000 phosphate; AkzoNobel's Morwet D425.

[0100] The present invention is further described below in conjunction with specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art. The essential characteristics and remarkable effects of the present invention can be reflected from the following examples, and the described embodiments are part of the embodiments of the present invention, rather than all the embodiments, and therefore, they do not limit the present invention in any way, and those skilled in the art make some non-essential improvements and adjustments based on the content of the present invention, which all belong to the protection scope of the present invention.

[0101] Example 1

[0102] The structural formula of the weak cationic polycarboxylate containing nitrogen oxide structure in the dispersant composition for regulating the particle size of the pesticide suspension of this embodiment is as follows:

[0103]

[0104] The specific preparation method is as follows:

[0105] Take the following substances by mass: allyl alcohol alkoxy compound (n1 = 1, n2 = 2, n3 = 1, R1, R3, R 10 =H, R2 = CH3) 30 g, maleic anhydride monoesterified ethoxylated methylamino polyether (X is an oxygen atom, n4 = 0, n5 = 0, n6 = 1, R 14 For CH3, R 15 50 g of H), 490 g of isopropanol aqueous solution (isopropanol content is 22%) and 3 g of 3-mercaptopropionic acid are added to a reaction kettle, and the mixture is heated to 75° C. with stirring; 20 g of styrene and 5 g of an initiator ammonium persulfate / sodium bisulfite dissolved in 50 g of water are simultaneously added dropwise to the above solution over 2.5 hours, and the mixture is kept at 75° C. for reaction for 4 h. A pH regulator NaOH is added to the reaction kettle, and after adjusting the pH to 8.0, 14 g of 28% hydrogen peroxide is added at 75° C., and the mixture is kept at 80° C. for 4 h to remove isopropanol; an aqueous solution 1a of a weakly cationic polycarboxylate salt containing a nitrogen oxide structure having a solid content of 20% is obtained.

[0106] A method for preparing a dispersant composition is as follows:

[0107] The weak cationic polycarboxylate aqueous solution was converted into weak cationic polycarboxylate and polynaphthalenesulfonate SP-2818L in a weight ratio of 90:10, and the mixture was stirred at room temperature for 30 minutes to obtain a dispersant composition 1b after being uniformly mixed.

[0108] The same operation as above was performed to convert the polycarboxylate aqueous solution into weakly cationic polycarboxylate and polynaphthalenesulfonate SP-2818L in a weight ratio of 80:20 to obtain a dispersant composition 1c.

[0109] The same operation as above was performed to convert the polycarboxylate aqueous solution into weakly cationic polycarboxylate and polynaphthalenesulfonate SP-2818L in a weight ratio of 75:25 to obtain a dispersant composition 1d.

[0110] The same operation as above was performed to convert the polycarboxylate aqueous solution into weakly cationic polycarboxylate and polynaphthalenesulfonate SP-2818L in a weight ratio of 50:50 to obtain a dispersant composition 1e.

[0111] Example 2

[0112] The structural formula of the weak cationic polycarboxylate containing nitrogen oxide structure in the dispersant composition for regulating the particle size of the pesticide suspension of this embodiment is as follows:

[0113]

[0114] The specific preparation method is as follows:

[0115] Take the following substances by mass: allyl alcohol alkoxy compound (n1 = 1, n2 = 5, n3 = 1, R1, R3, R 10 =H, R2 = CH3) 35 g, maleic anhydride monoesterified ethoxylated methylamino polyether (X is an oxygen atom, n4 = 0, n5 = 0, n6 = 1, R 14 For CH3, R 15 50 g of H), 490 g of isopropanol aqueous solution (isopropanol content is 22%) and 3 g of 3-mercaptopropionic acid are added to a reaction kettle, and the mixture is heated to 75° C. with stirring; 15 g of styrene and 5 g of an initiator ammonium persulfate / sodium bisulfite dissolved in 50 g of water are simultaneously added dropwise to the above solution over 2.5 hours, and the mixture is kept at 75° C. for reaction for 4 h, and a pH regulator NaOH is added to the reaction kettle to adjust the pH to 8.0, and 14 g of 28% hydrogen peroxide is added at 75° C. The mixture is kept at 80° C. for 4 h, and the isopropanol is removed; and an aqueous solution 2a of a weakly cationic polycarboxylate salt containing a nitrogen oxide structure having a solid content of 20% is obtained.

[0116] A method for preparing a dispersant composition is as follows:

[0117] The weak cationic polycarboxylate aqueous solution was converted into weak cationic polycarboxylate and Morwet D425 in a weight ratio of 90:10 and mixed and stirred at room temperature for 30 minutes until uniform to obtain a dispersant composition 2b.

[0118] Example 3

[0119] The structural formula of the weak cationic polycarboxylate containing nitrogen oxide structure in the dispersant composition for regulating the particle size of the pesticide suspension of this embodiment is as follows:

[0120]

[0121] The specific preparation method is as follows:

[0122] Take the following substances by mass: allyl alcohol alkoxy compound (n1 = 1, n2 = 10, n3 = 1, R1, R3, R 10 =H, R2 = H) 30 g, maleic anhydride monoesterified ethoxylated methylamino polyether (X is an oxygen atom, n4 = 0, n5 = 0, n6 = 1, R 14 For CH3, R 1555g of H) , 490g of isopropanol aqueous solution (isopropanol content is 22%) and 3g of 3-mercaptopropionic acid are added to a reaction kettle, and the mixture is heated to 75°C with stirring; 15g of styrene and 6g of an initiator potassium persulfate / sodium bisulfite dissolved in 50g of water are simultaneously added dropwise to the above solution over 2.5 hours, and the mixture is kept at 75°C for reaction for 4h. A pH adjusting agent NaOH is added to the reaction kettle, and after adjusting the pH to 8.0, 14g of 28% hydrogen peroxide is added at 75°C, and the mixture is kept at 80°C for 4h to remove isopropanol; and an aqueous solution 3a of a weakly cationic polycarboxylate salt containing a nitrogen oxide structure having a solid content of 20% is obtained.

[0123] A method for preparing a dispersant composition is as follows:

[0124] The weak cationic polycarboxylate aqueous solution was converted into weak cationic polycarboxylate and lignin sulfonate REAX85A in a weight ratio of 90:10 and stirred at room temperature for 30 minutes to obtain a dispersant composition 3b after being uniformly mixed.

[0125] Example 4

[0126] The structural formula of the weak cationic polycarboxylate containing nitrogen oxide structure in the dispersant composition for regulating the particle size of the pesticide suspension of this embodiment is as follows:

[0127]

[0128] The specific preparation method is as follows:

[0129] Take the following substances by mass: allyl alcohol alkoxy compound (n1 = 1, n2 = 2, n3 = 1, R1, R3, R 10 =H, R2 = CH3) 30 g, maleic anhydride monoesterified ethoxylated methylamino polyether (X is an oxygen atom, n4 = 0, n5 = 0, n6 = 1, R 14 For CH3, R 15 50 g of H), 490 g of isopropanol aqueous solution (isopropanol content is 22%) and 3 g of 3-mercaptopropionic acid are added to a reaction kettle, and the mixture is heated to 75° C. with stirring; 20 g of acrylic acid and 5.5 g of an initiator ammonium persulfate / sodium bisulfite dissolved in 50 g of water are simultaneously added dropwise to the above solution over 2.5 hours, and the mixture is kept at 75° C. for reaction for 4 hours, and a pH regulator NaOH is added to the reaction kettle to adjust the pH to 8.0, and 16 g of 28% hydrogen peroxide is added at 75° C. The mixture is kept at 80° C. for 4 hours to remove isopropanol; and an aqueous solution 4a of a weakly cationic polycarboxylate salt containing a nitrogen oxide structure having a solid content of 20% is obtained.

[0130] A method for preparing a dispersant composition is as follows:

[0131] The weak cationic polycarboxylate aqueous solution was converted into weak cationic polycarboxylate and polynaphthalenesulfonate SP-2818L in a weight ratio of 70:30 and stirred at room temperature for 30 minutes to obtain a dispersant composition 4b.

[0132] Example 5

[0133] The structural formula of the weak cationic polycarboxylate containing nitrogen oxide structure in the dispersant composition for regulating the particle size of the pesticide suspension of this embodiment is as follows:

[0134]

[0135] The specific preparation method is as follows:

[0136] Take the following substances by mass: allyl alcohol alkoxy compound (n1 = 1, n2 = 2, n3 = 1, R1, R3, R 10 =H, R2 = CH3) 30 g, maleic anhydride monoesterified ethoxylated methylamino polyether (X is an oxygen atom, n4 = 0, n5 = 0, n6 = 1, R 14 For CH3, R 15 50 g of H), 490 g of isopropanol aqueous solution (isopropanol content is 22%) and 3 g of dodecyl mercaptan are added to a reaction kettle, and the mixture is heated to 75° C. with stirring; 20 g of methyl methacrylate and 5 g of an initiator ammonium persulfate / sodium bisulfite dissolved in 50 g of water are simultaneously added dropwise to the above solution over 2.5 hours, and the mixture is kept at 75° C. for 4 hours, and a pH regulator NaOH is added to the reaction kettle to adjust the pH to 8.0, and 15 g of 28% hydrogen peroxide is added at 75° C. The mixture is kept at 80° C. for 4 hours to remove isopropanol; and an aqueous solution 5a of a weakly cationic polycarboxylate salt containing a nitrogen oxide structure having a solid content of 20% is obtained.

[0137] A method for preparing a dispersant composition is as follows:

[0138] The weak cationic polycarboxylate aqueous solution was converted into weak cationic polycarboxylate and polynaphthalenesulfonate SP-2818L in a weight ratio of 80:20 and stirred at room temperature for 30 minutes to obtain a dispersant composition 5b.

[0139] Example 6

[0140] The structural formula of the weak cationic polycarboxylate containing nitrogen oxide structure in the dispersant composition for regulating the particle size of the pesticide suspension of this embodiment is as follows:

[0141]

[0142] The specific preparation method is as follows:

[0143] Take the following substances by mass: allyl alcohol alkoxy compound (n1 = 1, n2 = 2, n3 = 1, R1, R3, R 10 =H, R2 = CH3) 30 g, maleic anhydride monoesterified ethoxylated methylamino polyether (X is an oxygen atom, n4 = 0, n5 = 0, n6 = 1, R 14 For CH3, R 15 50 g of H), 490 g of isopropanol aqueous solution (isopropanol content is 22%) and 3 g of bisbenzyl trithiocarbonate are added to a reaction kettle, and the mixture is heated to 75° C. with stirring; 20 g of methyl acrylate and 5 g of an initiator ammonium persulfate / sodium bisulfite dissolved in 50 g of water are simultaneously added dropwise to the above solution over 2.5 hours, and the mixture is kept at 75° C. for 4 hours, and a pH regulator NaOH is added to the reaction kettle to adjust the pH to 8.0, and 16 g of 28% hydrogen peroxide is added at 75° C. The mixture is kept at 80° C. for 4 hours to remove isopropanol; and an aqueous solution 6a of a weakly cationic polycarboxylate salt containing a nitrogen oxide structure having a solid content of 20% is obtained.

[0144] A method for preparing a dispersant composition is as follows:

[0145] The weak cationic polycarboxylate aqueous solution was converted into weak cationic polycarboxylate and polynaphthalenesulfonate SP-2818L in a weight ratio of 75:25 and stirred at room temperature for 30 minutes to obtain a dispersant composition 6b after being uniformly mixed.

[0146] Example 7

[0147] The structural formula of the weak cationic polycarboxylate containing nitrogen oxide structure in the dispersant composition for regulating the particle size of the pesticide suspension of this embodiment is as follows:

[0148]

[0149] The specific preparation method is as follows:

[0150] Take the following substances by mass: allyl alcohol alkoxy compound (n1 = 1, n2 = 5, n3 = 1, R1, R3, R 10 =H, R2 = CH3) 35 g, maleic anhydride monoesterified ethoxylated dodecylamine polyether (X is an oxygen atom, n4 = 2, n5 = 2, n6 = 0, R 14 For H, R 15 A straight chain saturated alkyl C 12 H 25) 50g, isopropanol aqueous solution (isopropanol content is 22%) 490g and dicarboxymethyl trithiocarbonate 3g are added into a reaction kettle, and heated to 75°C with stirring; methyl methacrylate 15g and an aqueous solution prepared by dissolving 5g initiator ammonium persulfate / sodium bisulfite in 50g water are simultaneously added dropwise into the above solution within 2.5 hours, and the mixture is kept at 75°C for reaction for 4h, pH regulator NaOH is added into the reaction kettle, and after adjusting the pH to 8.0, 28% hydrogen peroxide 14g is added at 75°C, and the mixture is kept at 80°C for 4h to remove isopropanol; and a weak cationic polycarboxylate aqueous solution 7a having a nitrogen oxide structure and a solid content of 20% is obtained.

[0151] A method for preparing a dispersant composition is as follows:

[0152] The weak cationic polycarboxylate aqueous solution was converted into weak cationic polycarboxylate and Tersperse 2500 in a weight ratio of 85:15 and stirred at room temperature for 30 minutes to obtain a dispersant composition 7b after being uniformly mixed.

[0153] Example 8

[0154] The structural formula of the weak cationic polycarboxylate containing nitrogen oxide structure in the dispersant composition for regulating the particle size of the pesticide suspension of this embodiment is as follows:

[0155]

[0156] The specific preparation method is as follows:

[0157] Take the following substances by mass: allyl alcohol alkoxy compound (n1 = 1, n2 = 5, n3 = 1, R1, R3, R 10 =H, R2 = CH3) 35 g, maleic anhydride monoesterified ethoxylated dodecylamine polyether (X is an oxygen atom, n4 = 7, n5 = 7, n6 = 0, R 14 For H, R 15 A straight chain saturated alkyl C 12 H 25 ) 50g, isopropanol aqueous solution (isopropanol content is 22%) 490g and mercaptoethanol 3g are added into a reaction kettle, and heated to 75°C with stirring; methyl methacrylate 15g and an aqueous solution prepared by dissolving 5g initiator ammonium persulfate / sodium bisulfite in 50g water are simultaneously added dropwise into the above solution within 2.5 hours, and the mixture is kept at 75°C for reaction for 4h, pH regulator NaOH is added into the reaction kettle, and after adjusting the pH to 8.0, 28% hydrogen peroxide 14g is added at 75°C, and the mixture is kept at 80°C for 4h to remove isopropanol; and an aqueous solution 8a of a weakly cationic polycarboxylate salt containing a nitrogen oxide structure with a solid content of 20% is obtained.

[0158] A method for preparing a dispersant composition is as follows:

[0159] The weak cationic polycarboxylate aqueous solution was converted into weak cationic polycarboxylate and SP-27001 in a weight ratio of 80:20 and stirred at room temperature for 30 minutes to obtain a dispersant composition 8b after being uniformly mixed.

[0160] Example 9

[0161] The structural formula of the weak cationic polycarboxylate containing nitrogen oxide structure in the dispersant composition for regulating the particle size of the pesticide suspension of this embodiment is as follows:

[0162]

[0163] The specific preparation method is as follows:

[0164] Take the following substances by mass: allyl alcohol alkoxy compound (n1 = 1, n2 = 5, n3 = 1, R1, R3, R 10 =H, R2 = CH3) 35 g, maleic anhydride monoesterified ethoxylated octadecylamine polyether (X is an oxygen atom, n4 = 7, n5 = 7, n6 = 0, R 14 For H, R 15 A straight chain saturated alkyl C 18 H 37 ) 50g, isopropanol aqueous solution (isopropanol content is 22%) 490g and thioglycolic acid 3g are added into a reaction kettle, and heated to 75°C with stirring; methyl methacrylate 15g and an aqueous solution prepared by dissolving 5g initiator ammonium persulfate / sodium bisulfite in 50g water are simultaneously added dropwise into the above solution within 2.5 hours, and the mixture is kept at 75°C for reaction for 4h, pH regulator NaOH is added into the reaction kettle, and after adjusting the pH to 8.0, 28% hydrogen peroxide 14g is added at 75°C, and the mixture is kept at 80°C for 4h to remove isopropanol; and an aqueous solution 8a of a weakly cationic polycarboxylate salt containing a nitrogen oxide structure with a solid content of 20% is obtained.

[0165] A method for preparing a dispersant composition is as follows:

[0166] The weak cationic polycarboxylate aqueous solution was converted into weak cationic polycarboxylate and polynaphthalenesulfonate SP-2728 in a weight ratio of 75:25 and stirred at room temperature for 30 minutes to obtain a dispersant composition 8b after being uniformly mixed.

[0167] Example 10

[0168] The structural formula of the weak cationic polycarboxylate containing nitrogen oxide structure in the dispersant composition for regulating the particle size of the pesticide suspension of this embodiment is as follows:

[0169]

[0170] The specific preparation method is as follows:

[0171] Take the following mass of substances: allyl alcohol alkoxy compound (n1 = 1, n2 = 5, n3 = 1, R1, R3, R 10 =H, R2 = CH3) 35 g, maleic anhydride monoesterified ethoxylated dimethylamine (X is an oxygen atom, n4 = 0, n5 = 0, n6 = 0, R 14 For CH3, R 15 50g of CH3), 490g of isopropanol aqueous solution (isopropanol content is 22%) and 3g of dicarboxylic isopropyl trithiocarbonate are added to a reaction kettle, and heated to 75°C with stirring; 15g of methyl methacrylate and 5g of an initiator ammonium persulfate / sodium bisulfite dissolved in 50g of water are simultaneously added dropwise to the above solution within 2.5 hours, and the mixture is kept at 75°C for 4h. A pH regulator NaOH is added to the reaction kettle, and after adjusting the pH to 8.0, 14g of 28% hydrogen peroxide is added at 75°C, and the mixture is kept at 80°C for 4h to remove isopropanol; an aqueous solution 10a of a weakly cationic polycarboxylate salt containing a nitrogen oxide structure with a solid content of 20% is obtained.

[0172] A method for preparing a dispersant composition is as follows:

[0173] The weak cationic polycarboxylate aqueous solution was converted into weak cationic polycarboxylate and polynaphthalenesulfonate SP-2818L in a weight ratio of 50:50 and stirred at room temperature for 30 minutes to obtain a dispersant composition 10b after being uniformly mixed.

[0174] Embodiment 11

[0175] The structural formula of the weak cationic polycarboxylate containing nitrogen oxide structure in the dispersant composition for regulating the particle size of the pesticide suspension of this embodiment is as follows:

[0176]

[0177] The specific preparation method is as follows:

[0178] Take the following mass of substances: allyl alcohol alkoxy compound (n1 = 1, n2 = 5, n3 = 1, R1, R3, R 10 =H, R2 is CH3) 35g, maleic anhydride monoamidated ethylamine dimethylamine (X is a nitrogen atom, n4=0, n5=0, n6=0, R 14 For CH3, R 1550 g of CH3), 490 g of isopropanol aqueous solution (isopropanol content is 22%) and 3 g of octanol are added to a reaction kettle, and heated to 75°C with stirring; 15 g of methyl methacrylate and 5 g of an initiator ammonium persulfate / sodium bisulfite dissolved in 50 g of water are simultaneously added dropwise to the above solution within 2.5 hours, and the mixture is kept at 75°C for reaction for 4 hours. A pH regulator NaOH is added to the reaction kettle, and after adjusting the pH to 8.0, 14 g of 28% hydrogen peroxide is added at 75°C, and the mixture is kept at 80°C for 4 hours to remove the isopropanol; an aqueous solution 11a of a weakly cationic polycarboxylate salt containing a nitrogen oxide structure with a solid content of 20% is obtained.

[0179] A method for preparing a dispersant composition is as follows:

[0180] The weak cationic polycarboxylate aqueous solution was converted into weak cationic polycarboxylate and SP-DF2238 in a weight ratio of 80:20 and stirred at room temperature for 30 minutes to obtain a dispersant composition 11b after being uniformly mixed.

[0181] Example 12

[0182] The structural formula of the weak cationic polycarboxylate containing nitrogen oxide structure in the dispersant composition for regulating the particle size of the pesticide suspension of this embodiment is as follows:

[0183]

[0184] The specific preparation method is as follows:

[0185] Take the following mass of substances: allyl alcohol alkoxy compound (n1 = 1, n2 = 5, n3 = 1, R1, R3, R 10 In the reaction kettle, 35g of methyl methacrylate and 5g of an initiator ammonium persulfate / sodium bisulfite dissolved in 50g of water were added dropwise over 2.5 hours, and the mixture was kept at 75°C for 4h. A pH adjusting agent NaOH was added to the reaction kettle, and after adjusting the pH to 8.0, 14g of 28% hydrogen peroxide was added at 75°C, and the mixture was kept at 80°C for 4h to remove the isopropanol. An aqueous solution 12a of a weakly cationic polycarboxylate salt containing a nitrogen oxide structure and having a solid content of 20% was obtained.

[0186] A method for preparing a dispersant composition is as follows:

[0187] The weak cationic polycarboxylate aqueous solution is converted into weak cationic polycarboxylate and YUS-FS3000 phosphate in a weight ratio of 80:20 and mixed and stirred at room temperature for 30 minutes to obtain a dispersant composition 12b.

[0188] Comparative Example 1

[0189] A method for preparing a dispersant composition is as follows:

[0190] The polymer sample with a solid content of 20% for improving the compatibility of pesticide formulations and concentrated fertilizers prepared in Example 1 of Chinese patent No. CN112574357A, a polymer for improving the compatibility of pesticide formulations and concentrated fertilizers and its preparation method, was converted into cationic polycarboxylate and polynaphthalenesulfonate SP-2818L in a weight ratio of 80:20 and mixed and stirred at room temperature for 30 minutes to obtain a dispersant composition 13b after being uniformly mixed.

[0191] Comparative Example 2

[0192] A method for preparing a dispersant composition is as follows:

[0193] The polymer sample with a solid content of 20% for improving the compatibility of pesticide formulations and concentrated fertilizers prepared in Example 1 of Chinese patent No. CN112574357A, a polymer for improving the compatibility of pesticide formulations and concentrated fertilizers and its preparation method, was converted into cationic polycarboxylate and YUS-FS3000 phosphate in a weight ratio of 80:20 and mixed and stirred at room temperature for 30 minutes to obtain a dispersant composition 14b after being uniformly mixed.

[0194] Comparative Example 3

[0195] A method for preparing a dispersant composition is as follows:

[0196] The polymer sample for improving the compatibility of pesticide formulations and concentrated fertilizers with a solid content of 20% prepared in Example 1 of Chinese patent "A polymer for improving the compatibility of pesticide formulations and concentrated fertilizers and its preparation method" with publication number CN112574357A was converted into cationic polycarboxylate and lignin sulfonate REAX 85A in a weight ratio of 90:10, mixed and stirred at room temperature for 30 minutes, and the dispersant composition 15b was obtained after being uniformly mixed.

[0197] Comparative Example 4

[0198] A method for preparing a dispersant composition is as follows:

[0199] The polymer sample with a solid content of 20% for improving the compatibility of pesticide formulations and concentrated fertilizers prepared in Example 1 of Chinese patent No. CN112574357A, a polymer for improving the compatibility of pesticide formulations and concentrated fertilizers and its preparation method, was converted into cationic polycarboxylate and polycarboxylate SP-DF2238 in a weight ratio of 80:20 and mixed and stirred at room temperature for 30 minutes to obtain a dispersant composition 16b after being uniformly mixed.

[0200] Comparative Example 5

[0201] A method for preparing a dispersant composition is as follows:

[0202] The polymer sample with a solid content of 20% for improving the compatibility of pesticide formulations and concentrated fertilizers prepared in Example 1 of Chinese patent No. CN112574357A, a polymer for improving the compatibility of pesticide formulations and concentrated fertilizers and its preparation method, was converted into cationic polycarboxylate and polycarboxylate SP-2728 in a weight ratio of 75:25 and mixed and stirred at room temperature for 30 minutes to obtain a dispersant composition 17b after being uniformly mixed.

[0203] Comparative Example 6

[0204] A method for preparing a dispersant composition is as follows:

[0205] The polymer sample with a solid content of 20% for improving the compatibility of pesticide formulations and concentrated fertilizers prepared in Example 1 of Chinese patent No. CN112574357A, a polymer for improving the compatibility of pesticide formulations and concentrated fertilizers and its preparation method, was converted into cationic polycarboxylate and polycarboxylate SP-27001 in a weight ratio of 80:20 and mixed and stirred at room temperature for 30 minutes to obtain a dispersant composition 18b after being uniformly mixed.

[0206] Application Examples

[0207] 1. The following application examples are used to prepare the suspension according to the following steps. The raw materials and proportions used are shown in Table 1:

[0208] 1) First, take part of the water and all the xanthan gum to form a 2 wt% xanthan gum solution.

[0209] 2) dissolving a commercially available dispersant or a dispersant composition in an embodiment or a comparative example, a wetting agent, an antifreeze agent, and a portion of a defoaming agent in the remaining water to obtain a first solution;

[0210] 3) adding the active ingredient of the pesticide and part of the defoamer into the first solution and shearing and dispersing them using a high-speed shearing machine, and then sand-grinding them using a sand mill until D90 is ≤ 5 μm to obtain a second solution;

[0211] Wherein, the shear dispersion time is 2 minutes.

[0212] The rotation speed of the shear dispersion is 2000 r / min.

[0213] 4) adding the remaining defoamer and thickener (magnesium aluminum silicate, 2 wt% xanthan gum solution) into the second solution, and stirring and dispersing with a stirrer to obtain the suspension.

[0214] Table 1 Raw materials and proportions used in different application examples

[0215]

[0216] 2. Dispersion performance test method:

[0217] The viscosity (unit: mpas) was measured using a digital rotational viscometer with rotor No. 3 selected at a rotation speed of 60 rpm to measure the viscosity of the sample.

[0218] The samples stored at room temperature for 2 months and hot stored for 14 days were measured by Malvern Laser Particle Sizer 3000. The measurements were repeated three times and the average was taken.

[0219] Low temperature stability shall be in accordance with 2.2 “Suspension preparations” in GB / T 19137-2003;

[0220] Thermal storage stability shall be carried out according to the method of 2.1 "Liquid Preparations" in GB / T 19136-2003;

[0221] The suspension rate is determined in accordance with 4.4 of GB / T 14825-2006;

[0222] Application Example 1

[0223] The test results of various properties of different dispersants or dispersant combinations on 5% avermectin + 40% spiroclofen SC are shown in Table 2:

[0224] Table 2 Test results of various properties of different dispersants or dispersant combinations on 5% avermectin + 40% spiroclofonate SC

[0225]

[0226]

[0227] Application Example 2

[0228] The test results of various properties of 50% thiazinone SC using different dispersants or dispersant combinations are shown in Table 3.

[0229] Table 3 Test results of various properties of different dispersants or dispersant combinations on 50% thiazinone SC

[0230]

[0231]

[0232] Application Example 3

[0233] The test results of various properties of 480 g / L metribuzin SC using different dispersants or dispersant combinations are shown in Table 4.

[0234] Table 4 Test results of various properties of different dispersants or dispersant combinations on 480g / L metribuzin SC

[0235]

[0236]

[0237] Application Example 4

[0238] Table 5 shows the test results of various properties of 8% flufenacet+24% flufenacet SC using different dispersants or dispersant combinations.

[0239] Table 5 Test results of various properties of different dispersants or dispersant combinations on 8% flufenacet + 24% flufenacet SC

[0240]

[0241]

[0242] It can be clearly seen from the data in Tables 2 to 5 that the composition of the weakly positive polycarboxylate prepared by the method disclosed in Examples 1b to 12b of the present invention and different anionic dispersants is used to prepare 5% avermectin + 40% spiroclofonate SC, 50% thiamethoxam SC, 8% flufenacet + 24% flufenacet SC and 480 g / L metribuzin SC, which can significantly improve the evaluation indicators such as suspension rate and heat storage stability, reduce the heat storage particle size change rate, and inhibit the particle size growth in the suspension. Compared with the competing products, whether it is a single lignin sulfonate or polycarboxylate or polynaphthalene sulfonate or the cationic and anionic dispersant composition in the comparative example, the composition in the embodiment has good compatibility with the wetting agent, which effectively solves the problem of gradually increasing viscosity and difficulty in processing and grinding during the preparation of high-content SC, resulting in the inability to discharge the material; coupled with the structural characteristics of the dispersant composition itself, the synergistic effect of providing high steric hindrance and high adsorption at the same time easily forms the same electrical layer repulsion, and the pesticide particles are dispersed and stably in the system without agglomeration, effectively solving the problem of difficult particle size control; during storage, the particle size grows, the viscosity increases, adheres to the container, delaminates, and becomes paste-like. In addition, by adjusting the different proportions of the two components of the dispersant composition, different application performances can be exhibited for different SC formulas to achieve the best effect.

[0243] The application effect shown by the above preparations is due to the good compatibility of the two components in the dispersant composition, which plays a synergistic role. By analyzing the molecular structure of the original drug in the preparation, it is found that most of the original drug molecules contain aromatic rings and heteroatoms such as nitrogen, oxygen, phosphorus and sulfur. The dispersant composition in the embodiment of the present invention provides a large number of naphthalene rings, benzene rings, and alkyl groups that can be closely combined with aromatic rings through dispersion forces; the weak cationic structure of nitrogen oxides can strongly adsorb heteroatoms with certain electronegativity, making the package very tight; in addition, the electrostatic repulsion of the hydrophilic groups of sulfonic acid groups and carboxylic acid groups and the steric hindrance generated by the macromolecular structure of the dispersant itself can ensure the low viscosity and dispersion stability of the grinding system, thereby ensuring that the growth of particle size and high suspension rate are effectively suppressed during the heat storage process.

Claims

1. A weak cationic polycarboxylate, characterized in that: The weak cationic polycarboxylate has a structure as shown in the following formula: Where: R is any one, two or three of -CH2-O-, -CH2 CH2-O-, -OCH2 CH2 CH2 CH2-O-; R1 is any one, two or three of -H, -CH3, -CH2 CH3; R2 is any one, two or three of -H, -CH3, -CH2 CH3; R3 is any one, two or three of -H, -CH3, -CH2 CH3; R4 is -H; R5 is any one or both of -H and -CH3; R6 is any one, two or three of -H, -CH3, -CH2 CH3; R7 is any one, two or three of -H, -CH3, -CH2 CH3; R8 is any one, two or three of -H, -CH3, -CH2 CH3; R9 is phenyl, -CONH2, -C4H6NO, -CH2 O(C2 H4 O) a (C3 H6 O) b H.COOR 3 Any one, two or more of the following; Wherein, a is any integer from 1 to 50, b is any integer from 0 to 50, R 3 Any one, two or more of sodium ion, potassium ion or ammonium ion, C1-C20 alkyl group, aralkyl group, and polyoxyethylene oxypropylene chain; R 10 Any one or two of -H, -OOCCH3; R 11 is any one or two of -H, -COOM; wherein M is any one, two or more of sodium ion, potassium ion or ammonium ion; R 12 Any one or both of -H and -CH3; R 13 Any one or both of the following structures Among them, R 14 is any one or two of H, a linear or branched, saturated or unsaturated alkyl group having 1 to 21 carbon atoms; R 15 is any one or two of H, a linear or branched, saturated or unsaturated alkyl group having 1 to 21 carbon atoms; X is any one of nitrogen or oxygen; n1, n2, n3 are all integers between 1 and 34; n4, n5, n6 are all integers between 0 and 10; n is the weight percentage of monomer A and is 10 to 40%; m is the weight percentage of monomer B and is 10 to 40%; q is the weight percentage of monomer C and is 20 to 60%.

2. A method for preparing a weak cationic polycarboxylate according to claim 1, characterized in that: The following steps are involved: S1, adding reaction monomer A, reaction monomer C, and chain transfer agent into an isopropanol aqueous solution, stirring and heating under reflux to obtain a mixed solution; and dropwise adding reaction monomer B and initiator solution into the mixed solution; S2. After the addition is completed, the mixture is kept warm and refluxed, and then the pH is adjusted to alkaline; S3, performing oxidative amination reaction; Wherein, in step S1, the reaction monomer A is one of an alkoxylate of allyl alcohol, an alkoxylate of methyl allyl alcohol, an alkoxylate of isopentenol, an alkoxylate of 4-hydroxybutyl vinyl ether or an acetate derivative thereof; The reactive monomer B is one of styrene, acrylic acid, methyl methacrylate, methyl acrylate, methyl styrene, allyl polyether, polyethylene glycol monoacrylate, and polyoxyethylene acrylic acid ether; The reactive monomer C is one of the derivatives of alkylamino polyether and acrylate, the derivatives of alkylamino polyether and maleic anhydride ester, the amide derivatives of alkylamino polyether and acrylic acid, or vinyl pyrrolidone.

3. The method for preparing a weakly cationic polycarboxylate according to claim 2, wherein: In step S1, the mass ratio of the reaction monomer A, the reaction monomer B, and the reaction monomer C is (1-4):(1-4):(2-6).

4. The method for preparing the dispersant composition according to claim 3, characterized in that: In step S1, the heating temperature is 60-90°C; In step S1, the dropping time is 1 to 4 hours.

5. The method for preparing the weakly cationic polycarboxylate according to any one of claims 2 to 4, characterized in that: In step S1, the amount of the chain transfer agent used is 0.5% to 10% of the sum of the amounts of the reaction monomer A, the reaction monomer B and the reaction monomer C, calculated by mass.

6. The method for preparing the weakly cationic polycarboxylate according to claim 5, characterized in that: In step S1, the amount of the initiator used is 2% to 16% of the sum of the amounts of the reaction monomer A, the reaction monomer B and the reaction monomer C, calculated by mass.

7. A dispersant composition, characterized in that: The dispersant composition comprises a weak cationic polycarboxylate and an anionic dispersant; The anionic dispersant includes one or more of polynaphthalene sulfonate, polycarboxylate, lignin sulfonate, and phosphate ester salt.

8. The dispersant composition according to claim 7, characterized in that: Calculated by mass, the mass of the weak cationic polycarboxylate accounts for 50% to 100% of the mass of the dispersant composition, but is not 100%.

9. Use of the dispersant composition according to any one of claims 7 to 8, characterized in that: Used to prepare suspension concentrates of pesticides.

10. The use of the dispersant composition according to claim 9, characterized in that: Calculated by mass, the amount of the dispersant composition used accounts for 1% to 6% of the total amount of the suspending agent.

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