A pesticide suspension concentrate containing a complex dispersant and a preparation method thereof

Abstract

The application discloses a pesticide suspension agent containing a composite dispersant and a preparation method thereof, and comprises an active component, a composite dispersant, a thickening agent, a preservative, an antifoaming agent and water; the composite dispersant is prepared by uniformly mixing modified acrylic polymers and modified lignin; the mass ratio of the modified acrylic polymers to the modified lignin is 3-4:1; the modified acrylic polymers have the structure shown in the following formula A, wherein a:b:c:d=(3-5):(1-2):(10-15):(10-15). The pesticide suspension agent containing the composite dispersant has excellent dispersibility, high suspension rate and high pesticide adhesion rate.

Description

Technical Field

[0001] This invention relates to the field of pesticide suspension technology, specifically to a pesticide suspension containing a composite dispersant and its preparation method. Background Technology

[0002] In the management of agricultural pests, the combination of pesticides is an important means of delaying and solving the problem of pesticide resistance. Pesticide compound compositions with synergistic effects can broaden the control spectrum, reduce dosage, improve biological characteristics, reduce environmental pollution, have good environmental compatibility, and make pests less likely to develop resistance.

[0003] Pesticide formulations can broaden the insecticidal spectrum and delay the development of pesticide resistance in pests. By rationally combining multiple pesticides, effective control of crop pests can be achieved. However, the high concentrations of these formulations pose certain environmental hazards, and the active ingredients only exert their effects after contact, ingestion, or absorption by harmful organisms or protected organisms. Therefore, they must be processed into pesticide formulations with specific physicochemical properties.

[0004] With increasing environmental awareness, traditional pesticide formulations such as emulsifiable concentrates, which primarily use organic solvents as carriers, can no longer meet people's needs. Among various pesticide formulations, safe and environmentally friendly suspension concentrates have become one of the leading formulations in the 21st-century pesticide processing field. Suspension concentrates use water as a medium, aided by certain adjuvants, and are produced by grinding and pulverizing solid active ingredients to uniformly disperse in water, forming a stable, highly suspended, and free-flowing liquid-solid system with fine particles. They are characterized by small particle size, good dispersibility, good flowability, high suspension rate, high biological activity, low dosage, resistance to rain washout, low residue, and low toxicity to humans and animals. Dispersants are the most important adjuvants in suspension concentrates, playing a crucial role in pesticide formulation and in imparting optimal efficacy to the active ingredients.

[0005] However, existing suspensions have low suspension rates, poor dispersibility, and low pesticide adhesion rates, making them unsuitable for the preparation of compound pesticide suspensions.

[0006] Therefore, there is an urgent need for a pesticide suspension agent with high suspension rate, strong dispersibility and high pesticide adhesion rate. Summary of the Invention

[0007] Purpose of the invention: In view of the deficiencies of the prior art, the purpose of this invention is to provide a pesticide suspension containing a composite dispersant with high suspension rate, strong dispersibility and high pesticide adhesion rate, and a method for preparing the same.

[0008] Technical solution:

[0009] A pesticide suspension containing a compound dispersant, comprising an active ingredient, a compound dispersant, a thickener, a preservative, an antifoaming agent, and water;

[0010] The composite dispersant is prepared by uniformly mixing modified acrylic polymer and modified lignin;

[0011] The mass ratio of modified acrylic polymer to modified lignin in the composite dispersant is 3-4:1;

[0012] Based on a total mass fraction of 100%, the mass percentage of each component is as follows:

[0013]

[0014] The remainder is water.

[0015] This invention uses a composite dispersant, which can significantly improve the suspension rate, dispersibility, and pesticide adhesion rate of pesticide suspensions.

[0016] Furthermore, the modified acrylic polymer has the structure shown in Formula A:

[0017]

[0018] Where a:b:c:d=(3-5):(1-2):(10-15):(10-15).

[0019] The modified acrylic polymer of the present invention is obtained by copolymerization of acrylic acid, acrylamide, acrolein diethanol condensate and allyl triisopropylsilane, and has excellent dispersing ability and can be used as a superdispersant.

[0020] The modified acrylic polymer of the present invention comprises a portion of a highly polar polyether segment as an anchoring group, which can be adsorbed onto the surface of pesticide particles through interactions such as ionic bonds and covalent bonds, preventing dispersant detachment and thus significantly improving pesticide adhesion rate; another portion comprises carboxyl and amide groups as solvation bonds, which can have good compatibility with water; and it also contains a triisopropylsilane structure, which can give the molecule a relatively extended structure, thus exhibiting excellent dispersibility and significantly improving the suspension rate and dispersibility of the suspending agent.

[0021] Furthermore, the active component comprises tetrazolium amide and chlorfenapyr; the mass ratio of tetrazolium amide to chlorfenapyr is 1:2-3.

[0022] The present invention preferably uses a combination of tetrazolium amide and chlorfenapyr as the active ingredient, which has excellent broad-spectrum insecticidal ability, can effectively control pests and diseases, and can delay the development of pesticide resistance in pests.

[0023] Furthermore, the thickener is selected from at least one of sodium alginate, polyacrylate, or magnesium aluminum silicate;

[0024] The preservative is selected from at least one of sodium benzoate or Kathon;

[0025] The defoamer is selected from at least one of polydimethylsiloxane or n-octanol.

[0026] Furthermore, the modified acrylic polymer is prepared by the following steps:

[0027] (1) In a reactor, acrylic acid, acrylamide, acrolein diethanol, emulsifier and deionized water are stirred at a constant speed to prepare a pre-emulsion;

[0028] (2) Introduce protective gas into the reactor, add pre-emulsion and initiator, heat to 75-80℃, and stir the reaction for 2-3 hours at a speed of 300-400 r / min;

[0029] (3) Add allyltriisopropylsilane to the reactor in step (2), heat to 85-90°C, keep the reaction at this temperature for 40-60 minutes, cool to room temperature, and filter to obtain the modified acrylic polymer.

[0030] Furthermore, the molar ratio of acrolein diethanol condensate, allyl triisopropylsilane, acrylic acid and acrylamide is (3-5):(1-2):(10-15):(10-15).

[0031] Further, in step (1), the emulsifier is selected from sodium dodecyl sulfate or dodecylphenol polyoxyethylene ether; in step (2), the initiator is selected from ammonium persulfate, sodium persulfate or potassium persulfate.

[0032] Furthermore, the modified lignin is prepared by the following steps: adding tartaric acid, catalyst and deionized water to a reactor, stirring evenly, adding alkaline lignin, heating to 80-95℃, reacting for 3-6 hours, filtering, washing and drying to obtain the modified lignin.

[0033] The modified lignin in the composite dispersant of the present invention provides steric hindrance due to its natural network macromolecular structure, thereby maintaining the stability of the suspension. Furthermore, the modification of lignin with tartaric acid can improve the compatibility between lignin and polymers, thereby improving the dispersibility and stability of the pesticide suspension.

[0034] Furthermore, the mass ratio of alkaline lignin to tartaric acid is 8-10:1; the catalyst is selected from sodium hypophosphite or potassium hypophosphite.

[0035] The preparation method of any of the above-mentioned pesticide suspensions containing a composite dispersant includes the following steps: weighing each component in proportion, adding the active component to water, stirring thoroughly, adding the composite dispersant, thickener, preservative and defoamer, and stirring thoroughly to obtain the pesticide suspension containing the composite dispersant.

[0036] Beneficial effects:

[0037] (1) The pesticide suspension containing the composite dispersant provided by the present invention is prepared by using the composite dispersant. The modified acrylic polymer in the composite dispersant is obtained by copolymerization of acrylic acid, acrylamide, acrolein diethanol condensate and allyl triisopropylsilane. It has excellent dispersing ability and can be used as a superdispersant.

[0038] (2) The modified acrylic polymer in the pesticide suspension containing the composite dispersant provided by the present invention contains a part of a highly polar polyether segment as an anchoring group, which can be adsorbed onto the surface of pesticide particles through interactions such as ionic bonds and covalent bonds, preventing the dispersant from falling off, thereby significantly improving the pesticide adhesion rate; another part contains carboxyl and amide groups as solvation bonds, which can have good compatibility with water; and also contains a triisopropylsilane structure, which can make the molecule have a relatively extended structure, thus having excellent dispersibility, and can significantly improve the suspension rate and dispersibility of the suspension.

[0039] (3) The pesticide suspension containing the composite dispersant provided by the present invention uses the composite dispersant to prepare the pesticide suspension. The modified lignin in the composite dispersant has a natural network macromolecular structure that provides steric hindrance, thereby maintaining the stability of the suspension. Furthermore, by modifying the lignin with tartaric acid, the compatibility between lignin and polymer can be improved, thereby improving the dispersibility and stability of the pesticide suspension.

[0040] (4) The pesticide suspension containing a composite dispersant provided by the present invention can significantly improve the suspension rate, dispersibility and pesticide adhesion rate of the pesticide suspension. Detailed Implementation

[0041] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0042] The commercially available dispersant was sodium methylene bisnaphthalene sulfonate purchased from Jinan Baoda Dyestuff Chemical Co., Ltd.; the polymeric dispersant was 40% sodium polyacrylate purchased from Guangzhou Yuanchang Trading Co., Ltd.; the alkaline lignin was L27580 purchased from Shanghai Jizhi Biochemical Technology Co., Ltd.; the remaining reagents and equipment were conventional reagents and equipment in this technical field.

[0043] Preparation of modified acrylic polymers

[0044] The modified acrylic polymer was prepared by the following steps:

[0045] (1) Add 0.15 mol acrylic acid, 0.15 mol acrylamide, 0.05 mol acrolein diethanolamide, 0.3 g sodium dodecyl sulfate and 100 mL deionized water to a 500 mL four-necked flask equipped with a condenser, a mechanical stirrer and a dropping funnel. Pre-emulsify on a magnetic stirrer for half an hour to prepare a pre-emulsion.

[0046] (2) Nitrogen gas was introduced into a 500 mL four-necked flask equipped with a condenser, a mechanical stirrer and a dropping funnel. The pre-emulsion prepared in step (1) and 0.3 g of ammonium persulfate were added. The mixture was heated to 80 °C, the stirrer was turned on and the speed was controlled at 350 r / min. The mixture was reacted for 3 hours.

[0047] (3) Add 0.02 mol of allyltriisopropylsilane to the reactor in step (2), heat to 90°C, keep the reaction at 90°C for 50 minutes, cool to room temperature, and filter to obtain the modified acrylic polymer.

[0048] Preparation of modified lignin

[0049] Modified lignin was prepared by the following steps:

[0050] Add 1g tartaric acid, 0.3g sodium hypophosphite and 50mL deionized water to the reactor, stir well, add 10g alkaline lignin, heat to 90℃, react for 4 hours, filter, wash and dry to obtain the modified lignin.

[0051] Example 1

[0052] Pesticide suspensions are prepared using the following steps:

[0053] Weigh each component according to the proportion, add the active component to water, stir thoroughly, then add the composite dispersant, sodium alginate, sodium benzoate and polydimethylsiloxane, stir thoroughly to obtain the pesticide suspension containing the composite dispersant;

[0054] The active components are tetrazolium amide and chlorfenapyr in a mass ratio of 1:3.

[0055] The composite dispersant is prepared by uniformly mixing modified acrylic polymer and modified lignin in a mass ratio of 4:1.

[0056] Based on a total mass fraction of 100%, the mass percentage of each component is as follows:

[0057]

[0058] The remainder is water.

[0059] Example 2

[0060] Basically the same as in Example 1, except that, based on a total mass fraction of 100%, the components and their mass percentages are as follows:

[0061]

[0062] The remainder is water.

[0063] Example 3

[0064] Basically the same as in Example 1, except that, based on a total mass fraction of 100%, the components and their mass percentages are as follows:

[0065]

[0066] The remainder is water.

[0067] Comparative Example 1

[0068] The method is basically the same as in Example 1, except that the composite dispersant is replaced with an equal amount of commercially available dispersant.

[0069] Comparative Example 2

[0070] The process is basically the same as in Example 1, except that the modified polypropylene polymer is replaced with an equal amount of polymeric dispersant.

[0071] Comparative Example 3

[0072] The method is basically the same as in Example 1, except that the modified polypropylene polymer is replaced with an equal amount of modified lignin.

[0073] Comparative Example 4

[0074] The basic formula is the same as in Example 1, except that the modified lignin is replaced with an equal amount of alkaline lignin.

[0075] Comparative Example 5

[0076] The method is basically the same as in Example 1, except that the modified lignin is replaced with an equal amount of modified polypropylene polymer.

[0077] Performance testing

[0078] Suspension rate test: The suspension rate of the products in Examples 1-3 and Comparative Examples 1-5 was tested according to GB / T14825-2006 Pesticide Suspension Rate Determination Method.

[0079] Pesticide adhesion rate test: Immerse a coverslip (2cm×2cm) vertically in the product solutions of Examples 1-3 and Comparative Examples 1-5 for 1 minute, remove it vertically and tilt it at 50° for 2 minutes, then measure the amount of pesticide on the coverslip and calculate the pesticide adhesion rate.

[0080] Dispersibility test: 249 mL of water and 1 mL of each of the products from Examples 1-3 and Comparative Examples 1-5 were added to a 250 mL graduated cylinder. The products were dropped into the water from a height of 5 cm above the water surface and the dispersion was observed. The dispersion was classified into three grades: excellent, good, and poor.

[0081] Superior grade: It disperses automatically in water in a mist-like form, with no visible particles settling.

[0082] Good grade: It can automatically disperse in water, with some particles settling. The settling particles can be slowly dispersed or dispersed after slight shaking.

[0083] Inferior grade: It cannot disperse automatically in water, sinks as particles, and can only disperse after strong shaking.

[0084] The test results are shown in the table below:

[0085] Suspension rate (%) Pesticide adhesion rate (%) Dispersion Example 1 96 86 excellent Example 2 95 86 excellent Example 3 95 87 excellent Comparative Example 1 57 48 inferior Comparative Example 2 78 66 good Comparative Example 3 67 64 inferior Comparative Example 4 85 73 inferior Comparative Example 5 81 69 good

[0086] According to the comparison of the test results of Examples 1-3 and Comparative Example 1, the pesticide suspension containing the composite dispersant provided by the present invention has a high suspension rate, strong dispersibility and high pesticide adhesion rate.

[0087] According to the comparison of the test results of Examples 1-3 and Comparative Examples 2 and 3, it can be seen that the pesticide suspension containing the composite dispersant provided by the present invention uses the composite dispersant, wherein the modified polypropylene polymer can significantly improve the pesticide adhesion rate, suspension rate and dispersibility of the pesticide suspension.

[0088] According to the comparison of the test results of Examples 1-3 and Comparative Examples 4 and 5, it can be seen that the pesticide suspension containing the composite dispersant provided by the present invention uses the composite dispersant, in which the modified lignin can significantly improve the dispersibility of the pesticide suspension.

[0089] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A pesticide suspension containing a composite dispersant, characterized in that, It contains active ingredients, compound dispersants, thickeners, preservatives, defoamers, and water; The composite dispersant is prepared by uniformly mixing modified acrylic polymer and modified lignin; The mass ratio of modified acrylic polymer to modified lignin in the composite dispersant is 3-4:1; Based on a total mass fraction of 100%, the mass percentage of each component is as follows: 40-50% active ingredients 3-5% of compound dispersant Thickener 1-3% Preservative 0.5-1% Defoamer 0.5-1% The remainder is water; The modified acrylic polymer has the structure shown in Formula A: ， Where a:b:c:d = (3-5):(1-2):(10-15):(10-15); The active components comprise tetrazolium amide and chlorfenapyr; the mass ratio of tetrazolium amide to chlorfenapyr is 1:2-3. The modified lignin is prepared by the following steps: tartaric acid, catalyst and deionized water are added to a reactor, stirred evenly, and then alkaline lignin is added. The temperature is raised to 80-95℃, and after reacting for 3-6 hours, the mixture is filtered, washed and dried to obtain the modified lignin.

2. The pesticide suspension containing a composite dispersant according to claim 1, characterized in that, The thickener is selected from at least one of sodium alginate, polyacrylate, or magnesium aluminum silicate. The preservative is selected from at least one of sodium benzoate or Kathon; The defoamer is selected from at least one of polydimethylsiloxane or n-octanol.

3. The pesticide suspension containing a composite dispersant according to claim 1, characterized in that, The modified acrylic polymer is prepared by the following steps: (1) In a reactor, acrylic acid, acrylamide, acrolein diethanol, emulsifier and deionized water are stirred at a constant speed to prepare a pre-emulsion; (2) Introduce protective gas into the reactor, add pre-emulsion and initiator, heat to 75-80℃, and stir for 2-3 hours at a speed of 300-400 r / min; (3) Add allyltriisopropylsilane to the reactor in step (2), heat to 85-90°C, keep the temperature for 40-60 minutes, cool to room temperature, and filter to obtain the modified acrylic polymer.

4. The pesticide suspension containing a composite dispersant according to claim 3, characterized in that, The molar ratio of acrolein diethanol condensate, allyl triisopropylsilane, acrylic acid and acrylamide is (3-5):(1-2):(10-15):(10-15).

5. The pesticide suspension containing a composite dispersant according to claim 3, characterized in that, In step (1), the emulsifier is selected from sodium dodecyl sulfate or dodecylphenol polyoxyethylene ether; in step (2), the initiator is selected from ammonium persulfate, sodium persulfate or potassium persulfate.

6. The pesticide suspension containing a composite dispersant according to claim 1, characterized in that, The mass ratio of alkaline lignin to tartaric acid is 8-10:1; the catalyst is selected from sodium hypophosphite or potassium hypophosphite.

7. A method for preparing a pesticide suspension containing a composite dispersant as described in any one of claims 1-6, characterized in that, The process includes the following steps: weighing each component according to the proportion, adding the active component to water, stirring thoroughly, adding the composite dispersant, thickener, preservative and defoamer, and stirring thoroughly to obtain the pesticide suspension containing the composite dispersant.

Images