Long-acting light-operated slow-release suspoemulsion herbicide and preparation method thereof

Abstract

The invention belongs to the technical field of herbicides, and particularly relates to a long-acting light-operated slow-release suspoemulsion type herbicide and a preparation method thereof, the long-acting light-operated slow-release suspoemulsion type herbicide comprises the following components by mass: 70-80 parts of a light-operated microcapsule herbicide, 2-5 parts of an emulsifier, 0.8-1 part of a dispersant, 0.2-0.4 part of a structure regulator, 0.2-0.4 part of an inorganic filler, 0.1-0.3 part of an antifoaming agent and 30-60 parts of water. The suspoemulsion type herbicide prepared by the invention can be prepared by a conventional two-step method or a simpler one-step method, and the obtained product is good in stability, low in viscosity, environment-friendly, long in lasting time of weeding effect and good in broad-spectrum weeding effect.

Description

Technical Field

[0001] The invention belongs to the technical field of herbicides, and particularly relates to a long-acting light-controlled slow-release suspoemulsion herbicide and a preparation method thereof. Background Art

[0002] Herbicides, also known as weed killers, are pesticides that can kill or control the growth of weeds. They inhibit the growth and development of weeds and protect crops, thereby improving agricultural output efficiency. Herbicides can be divided into selective herbicides and non-selective herbicides according to their mode of action. The former only targets specific types of weeds, while the latter kills all plants. The global herbicide market has shown a steady growth trend in recent years. With the growth of the global population and the reduction of cultivated land, the demand for increasing unit area yield has led to an increase in the use of herbicides year by year. In particular, with the expansion of genetically modified crop planting areas, the demand for non-selective herbicides has increased significantly. According to market research, it is expected that by 2025, the global herbicide industry market size will reach US$26.5 billion.

[0003] At present, the common formulations of herbicides can be divided into wettable powders, suspensions, emulsifiable concentrates, water emulsions and suspoemulsions. Among them, suspoemulsion-type herbicides are valued for their environmental friendliness and ease of use. Suspoemulsions are formed by combining an emulsified phase containing one or more active ingredients with a continuous phase also containing one or more active ingredients to form a solid dispersion. This formulation has the user advantage of being easy to transport, store and apply in the field. However, the preparation technology of suspoemulsion-type herbicides is highly challenging and complex, especially when the active ingredients are physically, chemically and biologically incompatible, and new formulations need to be developed to overcome the incompatibility problem. For example, patent CN1756481A discloses a "herbicidal suspoemulsion" which comprises a continuous phase and a dispersed phase, wherein the continuous phase comprises a block copolymer and a nonionic surfactant, the dispersed phase comprises chloroacetamide and a polymer stabilizer, and a dispersed solid phase comprising 2-(substituted benzoyl)-1,3-cyclohexanedione herbicide and a stabilized metal salt, and the stability of the suspoemulsion is improved by chelating mesotrione free acid and a metal chelator. Another example is CN111449071A discloses a "suspoemulsion type mixed herbicide and its production process" which is prepared by using clofopyralid, bispyribac, clodinafop-butyl, fatty alcohol polyoxyethylene ether sulfate, and magnesium aluminum silicate as main raw materials and compounding with other functional auxiliary ingredients. The suspoemulsion type mixed herbicide is safe for the environment, has good stability, and has significant synergistic effect, and improves the permeability and systemicity of the active ingredients.

[0004] However, currently herbicides need to be sprayed manually on a regular basis, which greatly increases labor costs. Therefore, it is urgent to develop a suspoemulsion herbicide with good stability, low viscosity, environmental friendliness, long-lasting weed control effect, and simple preparation process. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a long-acting light-controlled slow-release suspoemulsion herbicide and a preparation method thereof. The suspoemulsion herbicide has good stability, low viscosity, is environmentally friendly, has a long-lasting weed control effect and a good broad-spectrum weed control effect.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides a long-acting light-controlled slow-release suspoemulsion herbicide, comprising the following components in parts by weight: 70 to 80 parts of light-controlled microcapsule herbicide, 2 to 5 parts of emulsifier, 0.8 to 1 part of dispersant, 0.2 to 0.4 part of structure regulator, 0.2 to 0.4 part of inorganic filler, 0.1 to 0.3 part of defoamer and 30 to 60 parts of water.

[0008] The herbicides currently available on the market have obvious initial weed control effects, but in order to maintain the weed control effect for a longer period of time, it is necessary to manually spray the herbicides irregularly, which greatly wastes labor. The suspoemulsion herbicide of the present invention can maintain a long-term weed control effect after spraying. The daytime sunlight is the best period for weed growth. The light-controlled microcapsule herbicide in the suspoemulsion herbicide can slowly release the herbicide composition under sunlight to inhibit the growth of weeds and achieve the weed control effect. The slow-release effect can increase the duration of weed control efficiency, avoid periodic spraying of herbicides, and save labor.

[0009] In addition, conventional suspoemulsions often have high viscosity, poor dispersibility and stratification and precipitation. The present application, by adding inorganic fillers, can form the mutual repulsion of like charges in the system to destroy the structure of the associated micelles of surfactants in water, reduce the viscosity of the product, and at the same time, the synergistic structure regulator can improve the suspension state of the product, thereby preventing the stratification, sedimentation and bottoming of the product caused by the action of inorganic salts.

[0010] In some embodiments, the method for preparing the light-controlled microcapsule herbicide comprises the following steps:

[0011] S1, dissolving the herbicide composition in ethyl acetate as the oil phase;

[0012] S2, mixing the modified chitosan, the surfactant and water to obtain an aqueous phase;

[0013] S3, adding the oil phase in step S1 to the water phase in step S2 while stirring, and stirring until the mixture is uniform to obtain a microemulsion;

[0014] S4, mixing the microemulsion in step S3 with ethanol to obtain a mixed aqueous phase, and then adding a surfactant and continuing to stir to obtain a mixed solution;

[0015] S5. Add liquid paraffin dropwise into the mixed solution in step S4 under stirring, and obtain the light-controlled microcapsule herbicide after filtering.

[0016] The present application prepares the herbicide into oil-in-water-in-oil type microcapsules, wherein liquid paraffin is used as the outermost capsule wall. Under sunlight during the day, the surface temperature rises, the capsule wall melts, and the modified chitosan inside absorbs moisture in the air and slowly releases the herbicide composition therein as it degrades naturally, achieving a long-term weed control effect. The use of liquid paraffin as the capsule wall can also prevent water in the suspoemulsion type herbicide from invading, causing the modified chitosan therein to swell, thereby rupturing the capsule wall, causing the herbicide composition to flow out in advance, thereby worsening the slow-release effect and weakening the long-term weed control effect.

[0017] In some embodiments, the preparation method of the modified chitosan comprises the following steps: dissolving chitosan in a sodium hydroxide solution, heating to 60-65° C., adding an ultraviolet absorber and continuing stirring for 7-8 hours, cooling to room temperature after the reaction is completed, and obtaining the modified chitosan after drying.

[0018] The applicant found in the study that although the suspoemulsion herbicide can play a sustained release role, it is highly dependent on the intensity of sunlight and can only play a sustained release effect when the surface temperature reaches the melting temperature of paraffin, which greatly affects the initial weed control effect. The present application can reduce the problem of poor weed control effect caused by weather influence by modifying chitosan with specific raw materials. The reason may be that the modified chitosan contains a large amount of benzotriazole structure, which can give chitosan better ultraviolet absorption ability. The modified chitosan converts ultraviolet rays into heat energy to heat up the microcapsules and quickly reach the melting temperature of paraffin to release the herbicide composition, thereby improving the initial weed control effect.

[0019] In some embodiments, the herbicidal composition comprises atrazine, 2.4-D isooctyl ester and acetochlor; the mass ratio of atrazine, 2.4-D isooctyl ester and acetochlor is 1:(0.3-0.4):(0.9-1.1).

[0020] In some embodiments, the volume ratio of the herbicide composition to ethyl acetate is 1:(17-18).

[0021] Preferably, the volume ratio of the herbicide composition to ethyl acetate is 1:17.5.

[0022] In some embodiments, the volume ratio of the modified chitosan to water is 1:(10-12).

[0023] Preferably, the volume ratio of the modified chitosan to water is 1:11.

[0024] In some embodiments, in step S3, the mass ratio of the water phase to the oil phase is (2-5):1.

[0025] Preferably, in step S3, the mass ratio of the water phase to the oil phase is 3:1.

[0026] In some embodiments, in step S4, the mass ratio of the microemulsion, ethanol and surfactant is 1:(0.1-0.3):(2.3-2.6).

[0027] In some embodiments, in step S5, the mass ratio of the liquid paraffin to the surfactant in step S4 is 1:(2.3-3).

[0028] Preferably, in step S5, the mass ratio of the liquid paraffin to the surfactant in step S4 is 1:2.5.

[0029] In some embodiments, in step S5, the filtration uses a microporous filter membrane with a pore size of 1 to 8 μm.

[0030] In some embodiments, the ultraviolet absorber is any one of benzotriazoles, benzophenones, salicylates and substituted triazines.

[0031] In some embodiments, the mass ratio of chitosan to ultraviolet absorber is 1:(0.1-0.3).

[0032] Preferably, the mass ratio of chitosan to ultraviolet absorber is 1:0.2.

[0033] The present application can prevent the poor water solubility caused by large steric hindrance and the inability to well coat the herbicide composition by regulating the mass ratio of chitosan to ultraviolet absorber. At the same time, it can also prevent the low ultraviolet absorption capacity and reduced efficiency of converting heat energy, which will lead to a weakened sustained-release effect of the light-controlled microcapsule herbicide.

[0034] In some embodiments, the inorganic filler is a soluble chloride salt.

[0035] In some embodiments, the emulsifier is one or more of sodium dodecylbenzene sulfonate, polyoxyethylene styrylphenyl ether, polyoxyethylene dibenzylbiphenyl ether, polyoxyethylene phenylethylphenol formaldehyde resin ether, and polyoxyethylene-polyoxypropylene block polyether of polyoxyethylene styrylphenol formaldehyde resin.

[0036] In some embodiments, the structure regulator is one or more of xanthan gum, magnesium aluminum silicate, polymethyl cellulose, fumed silica and precipitated silica.

[0037] In some embodiments, the dispersant is polyvinyl pyrrolidone or polyvinyl alcohol.

[0038] Preferably, the structure regulator is magnesium aluminum silicate.

[0039] On the other hand, the present invention provides a method for preparing a long-acting light-controlled slow-release suspoemulsion herbicide, comprising the following steps: putting an emulsifier, a dispersant, a defoamer and water into a high-shear reactor, adding a light-controlled microcapsule herbicide, a structure regulator and an inorganic filler under a high shear state of 1000-1500 r / min, and continuing shearing for 20-30 minutes. After the shearing is completed, the long-acting light-controlled slow-release suspoemulsion herbicide is obtained.

[0040] In another aspect, the present invention provides a method for preparing a long-acting light-controlled slow-release suspoemulsion herbicide, comprising the following steps:

[0041] (1) adding a dispersant and an emulsifier into a stirring tank and stirring them uniformly to prepare an emulsion phase;

[0042] (2) adding water into a high shear reactor, adding a light-controlled microcapsule herbicide, a structure regulator, an inorganic filler and a defoamer at a speed of 1000 to 1500 r / min, and continuing to stir for 20 to 30 minutes after the addition is completed to obtain a suspension;

[0043] (3) pumping the emulsion phase in step (1) into the suspension in step (2) at a stirring rate of 800 to 1000 r / min, and continuing stirring for 15 to 20 minutes to obtain a long-acting light-controlled slow-release suspoemulsion herbicide.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] (1) The present invention uses light-controlled microcapsule herbicides, emulsifiers, dispersants, structure regulators, inorganic fillers, defoamers and water as main raw materials to prepare a suspoemulsion-type herbicide through two different preparation methods. The suspoemulsion-type herbicide has good stability and does not stratify or precipitate after long-term storage. It also has low viscosity, is environmentally friendly, has a long-lasting weed control effect and has a good broad-spectrum weed control effect.

[0046] (2) The light-controlled microcapsule herbicide of the present invention is an oil-in-water-in-oil type microcapsule. On the one hand, the use of liquid paraffin as the capsule wall can prevent the water in the suspoemulsion type herbicide from invading and causing the modified chitosan therein to swell and rupture the capsule wall, thereby causing the herbicide composition to flow out prematurely, further deteriorating the sustained-release effect and weakening the long-term herbicidal effect; on the other hand, the modified chitosan contains a large amount of benzotriazole structure, which can give the chitosan better ultraviolet absorption ability. The modified chitosan converts ultraviolet rays into heat energy, thereby raising the temperature of the microcapsule and quickly reaching the melting temperature of paraffin to slowly release the herbicide composition, thereby improving the initial herbicidal effect.

[0047] (3) The present invention can make the suspoemulsion herbicide of the present application not produce precipitation and stratification during long-term storage by regulating the specific addition amount of the structure regulator in coordination with the inorganic filler, and at the same time prevent the system from being too viscous to facilitate the one-step preparation of the herbicide. DETAILED DESCRIPTION

[0048] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, but not to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0049] In the following examples, polyvinyl alcohol was purchased from Kaimaoxing (Hebei) Cellulose Co., Ltd.

[0050] Preparation Example 1

[0051] The preparation method of modified chitosan comprises the following steps: dissolving 50g chitosan in 10L sodium hydroxide solution with a concentration of 8g / L, heating to 62°C, adding 10g 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole thereto, and continuing stirring for 7.5h, cooling to 27°C after the reaction is completed, and obtaining the modified chitosan after drying.

[0052] Preparation Example 2

[0053] The preparation method of modified chitosan comprises the following steps: dissolving 50g of chitosan in 10L of 8g / L sodium hydroxide solution, heating to 62°C, adding 10g of 1,2-dichloropropane thereto and continuing stirring for 7.5h, cooling to 27°C after the reaction is completed, drying to obtain a modified chitosan precursor, mixing the chitosan precursor with methanol, adding 13.8g of 2,2,6,6-tetramethylpiperidinamine and 9.5g of sodium carbonate, stirring at 27°C for 16h, drying after the reaction is completed, and obtaining the modified chitosan.

[0054] Preparation Example 3

[0055] The preparation method of modified chitosan is the same as that of Preparation Example 1, except that the added amount of 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole is 20 g.

[0056] Preparation Example 4

[0057] The preparation method of the light-controlled microcapsule herbicide comprises the following steps:

[0058] S1, dissolving 10 g of atrazine, 3.5 g of 2.4-isooctyl ester, and 10 g of acetochlor in 420 mL of ethyl acetate as the oil phase;

[0059] S2, mixing 70 g of modified chitosan, 20 g of EL-35 and 780 mL of water to obtain an aqueous phase;

[0060] S3, adding 200 g of the oil phase in step S1 to 600 g of the water phase in step S2 while stirring, and stirring until the mixture is uniform to obtain a microemulsion;

[0061] S4, 500 g of the microemulsion in step S3 and 100 g of ethanol were mixed to obtain a mixed aqueous phase, and 1200 g of EL-35 was added and stirred to obtain a mixed solution;

[0062] S5. Add 480 g of liquid paraffin dropwise into the mixed solution in step S4 under stirring, and filter with a 6 μm microporous filter membrane to obtain a light-controlled microcapsule herbicide.

[0063] Wherein, the modified chitosan is prepared by Preparation Example 1.

[0064] Preparation Example 5

[0065] The preparation method of the light-controlled microcapsule herbicide is the same as that of Preparation Example 4, except that the modified chitosan is prepared by Preparation Example 2.

[0066] Preparation Example 6

[0067] The preparation method of the light-controlled microcapsule herbicide is the same as that of Preparation Example 4, except that the modified chitosan is prepared by Preparation Example 3.

[0068] Preparation Example 7

[0069] The preparation method of the light-controlled microcapsule herbicide is the same as that of Preparation Example 4, except that an equal mass of chitosan is used instead of modified chitosan.

[0070] Example 1

[0071] A long-acting light-controlled slow-release suspoemulsion herbicide comprises the following components in parts by weight: 75 parts of light-controlled microcapsule herbicide, 3 parts of sodium dodecylbenzene sulfonate, 0.9 parts of polyvinyl alcohol, 0.3 parts of magnesium aluminum silicate, 0.3 parts of sodium chloride, 0.2 parts of dimethyl silicone oil and 45 parts of water.

[0072] Among them, the light-controlled microcapsule herbicide is prepared by Preparation Example 4.

[0073] The preparation method of a long-acting light-controlled sustained-release suspend-emulsion herbicide comprises the following steps: putting polyvinyl alcohol, sodium dodecylbenzene sulfonate, dimethyl silicone oil and water into a high-shear reactor, adding light-controlled microcapsule herbicide, magnesium aluminum silicate and sodium chloride under a high-shear state of 1300 r / min, and continuing shearing for 25 minutes. After the shearing is completed, the long-acting light-controlled sustained-release suspend-emulsion herbicide is obtained.

[0074] Example 2

[0075] A long-acting light-controlled slow-release suspoemulsion herbicide comprises the following components in parts by weight: 70 parts of light-controlled microcapsule herbicide, 2 parts of sodium dodecylbenzene sulfonate, 0.8 parts of polyvinyl alcohol, 0.2 parts of magnesium aluminum silicate, 0.2 parts of sodium chloride, 0.1 parts of dimethyl silicone oil and 30 parts of water.

[0076] Among them, the light-controlled microcapsule herbicide is prepared by Preparation Example 4.

[0077] The preparation method of a long-acting light-controlled slow-release suspend-emulsion herbicide comprises the following steps: putting polyvinyl alcohol, sodium dodecylbenzene sulfonate dimethyl silicone oil and water into a high-shear reactor, adding light-controlled microcapsule herbicide, magnesium aluminum silicate and sodium chloride under a high-shear state of 1000 r / min, and continuing shearing for 30 minutes. After the shearing is completed, the long-acting light-controlled slow-release suspend-emulsion herbicide is obtained.

[0078] Example 3

[0079] A long-acting light-controlled slow-release suspoemulsion herbicide comprises the following components in parts by weight: 80 parts of light-controlled microcapsule herbicide, 5 parts of sodium dodecylbenzene sulfonate, 1 part of polyvinyl alcohol, 0.4 parts of magnesium aluminum silicate, 0.4 parts of sodium chloride, 0.3 parts of dimethyl silicone oil and 60 parts of water.

[0080] Among them, the light-controlled microcapsule herbicide is prepared by Preparation Example 4.

[0081] The preparation method of a long-acting light-controlled slow-release suspend-emulsion herbicide comprises the following steps: putting polyvinyl alcohol, sodium dodecylbenzene sulfonate dimethyl silicone oil and water into a high-shear reactor, adding light-controlled microcapsule herbicide, magnesium aluminum silicate and sodium chloride under a high-shear state of 1500 r / min, and continuing shearing for 20 minutes. After the shearing is completed, the long-acting light-controlled slow-release suspend-emulsion herbicide is obtained.

[0082] Example 4

[0083] A long-acting light-controlled slow-release suspoemulsion herbicide comprises the following components in parts by weight: 75 parts of light-controlled microcapsule herbicide, 3 parts of sodium dodecylbenzene sulfonate, 0.9 parts of polyvinyl alcohol, 0.3 parts of magnesium aluminum silicate, 0.3 parts of sodium chloride, 0.2 parts of dimethyl silicone oil and 45 parts of water.

[0084] Among them, the light-controlled microcapsule herbicide is prepared by Preparation Example 4.

[0085] The preparation method of a long-acting light-controlled slow-release suspoemulsion herbicide comprises the following steps:

[0086] (1) adding sodium dodecylbenzene sulfonate and polyvinyl alcohol into a stirring tank and stirring them uniformly to prepare an emulsion phase;

[0087] (2) adding water into a high shear reactor, adding light-controlled microcapsule herbicide, magnesium aluminum silicate, sodium chloride and dimethyl silicone oil at a speed of 1300 r / min, and continuing to stir for 25 minutes after the addition is completed to obtain a suspension;

[0088] (3) The emulsion phase in step (1) is pumped into the suspension in step (2) at a stirring rate of 900 r / min, and stirring is continued for 17 minutes to obtain a long-acting light-controlled slow-release suspoemulsion herbicide.

[0089] Example 5

[0090] A long-acting light-controlled slow-release suspoemulsion herbicide and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the light-controlled microcapsule herbicide is prepared by Preparation Example 5.

[0091] Example 6

[0092] A long-acting light-controlled slow-release suspoemulsion herbicide and a preparation method thereof. The specific implementation manner is the same as Example 1, except that the light-controlled microcapsule herbicide is prepared by Preparation Example 6.

[0093] Example 7

[0094] A long-acting light-controlled slow-release suspoemulsion herbicide and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the light-controlled microcapsule herbicide is prepared by Preparation Example 7.

[0095] Comparative Example 1

[0096] A long-acting light-controlled slow-release suspoemulsion herbicide and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that an equal mass percentage of a herbicide composition is used instead of the light-controlled microcapsule herbicide, and the herbicide composition consists of atrazine, 2.4-D isooctyl ester and acetochlor in a mass ratio of 1:0.35:1.

[0097] Performance Testing:

[0098] (1) Dumping residue test: The test is conducted according to GB / T 31737-2015 "Determination of dumping property of pesticides". The more residue there is, the greater the viscosity of the suspoemulsion herbicide system.

[0099] (2) Stability test: Place the suspoemulsion herbicide at 27°C for 40 days and observe whether it precipitates and becomes paste at the bottom;

[0100] (3) Duration of weed control: According to GB / T 17980.49-2000 "Guidelines for Field Efficacy Tests of Pesticides (I) Control of Weeds in Sugarcane Fields by Herbicides", the test field containing broadleaf weeds and grass weeds was selected. The soil was black soil, and the test field was divided into blocks. A mixed dilution of 250g of suspoemulsion herbicide and 20kg of water was sprayed on each mu of land. One block of land was sprayed with water as a blank control group. The weed species and number were observed and recorded 10 days, 50 days, and 100 days after the application of the pesticide, and the control effect per plant was calculated by the following formula:

[0101] Plant protection efficiency (%) = (number of live weeds in the control area - number of remaining weeds in the treatment area) / (number of live weeds in the control area) × 100%.

[0102] The suspoemulsion herbicides prepared in the examples and comparative examples were tested according to the above test method. The results are shown in Table 1.

[0103] Table 1

[0104]

[0105] According to the data analysis in Table 1, the suspoemulsion herbicides of Examples 1 to 4 have low viscosity, are stable in storage, and have a long lasting weed control effect after one spraying; Example 5 uses 2,2,6,6-tetramethylpiperidinamine instead of 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole. Although both are ultraviolet absorbers, they absorb ultraviolet rays by capturing free radicals to improve the anti-ultraviolet effect, and the temperature rise is not obvious, resulting in poor sustained-release effect of the suspoemulsion herbicide; Example 6 changes the chitosan and 2'-(2'-hydroxy-3'-tert-butyl-5'- The mass ratio of 2-methylphenyl)-5-chlorobenzotriazole to 1-methylphenyl)-5-chlorobenzotriazole results in a slight increase in the viscosity of the suspoemulsion herbicide, and a significant increase in the initial weed control efficiency, but a weakened long-term weed control effect. In Example 7, since the same mass of chitosan is used instead of the modified chitosan, the microcapsules cannot heat up under daylight, resulting in a poor sustained-release effect. In Comparative Example 1, since the same mass percentage of the herbicide composition is used instead of the light-controlled microcapsule herbicide, since atrazine is directly present in the suspoemulsion herbicide, the viscosity of the system is slightly increased. In addition, since the herbicide composition is not coated, the duration of the herbicide efficacy is shortened, which is not conducive to long-term weed control.

[0106] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A long-acting light-controlled slow-release suspoemulsion herbicide, characterized in that: The composition comprises the following components in parts by weight: 70-80 parts of light-controlled microcapsule herbicide, 2-5 parts of emulsifier, 0.8-1 parts of dispersant, 0.2-0.4 parts of structure regulator, 0.2-0.4 parts of inorganic filler, 0.1-0.3 parts of defoamer and 30-60 parts of water.

2. A long-acting light-controlled slow-release suspoemulsion herbicide according to claim 1, characterized in that: The preparation method of the light-controlled microcapsule herbicide comprises the following steps: S1, dissolving the herbicide composition in ethyl acetate as the oil phase; S2, mixing the modified chitosan, the surfactant and water to obtain an aqueous phase; S3, adding the oil phase in step S1 to the water phase in step S2 while stirring, and stirring until the mixture is uniform to obtain a microemulsion; S4, mixing the microemulsion in step S3 with ethanol to obtain a mixed aqueous phase, and then adding a surfactant and continuing to stir to obtain a mixed solution; S5. Add liquid paraffin dropwise into the mixed solution in step S4 under stirring, and obtain the light-controlled microcapsule herbicide after filtering.

3. A long-acting light-controlled slow-release suspoemulsion herbicide according to claim 2, characterized in that: The preparation method of the modified chitosan comprises the following steps: dissolving chitosan in a sodium hydroxide solution, heating the solution to 60-65° C., adding an ultraviolet absorber thereto and stirring for 7-8 hours, cooling the solution to room temperature after the reaction is completed, and drying the solution to obtain the modified chitosan.

4. The long-acting light-controlled slow-release suspoemulsion herbicide according to claim 2, characterized in that: In step S5, the mass ratio of the liquid paraffin to the surfactant in step S4 is 1:(2.3-3).

5. The long-acting light-controlled slow-release suspoemulsion herbicide according to claim 3, characterized in that: The ultraviolet absorber is any one of benzotriazoles, benzophenones, salicylates and substituted triazines.

6. The long-acting light-controlled slow-release suspoemulsion herbicide according to claim 3, characterized in that: The mass ratio of chitosan to ultraviolet absorber is 1:(0.1-0.3).

7. The long-acting light-controlled slow-release suspoemulsion herbicide according to claim 1, characterized in that: The inorganic filler is a soluble chloride salt.

8. The long-acting light-controlled slow-release suspoemulsion herbicide according to claim 1, characterized in that: The emulsifier is one or more of sodium dodecylbenzene sulfonate, polyoxyethylene styrylphenyl ether, polyoxyethylene dibenzylbiphenyl ether, polyoxyethylene styrylphenol formaldehyde resin ether and polyoxyethylene-polyoxypropylene block polyether of polyoxyethylene styrylphenol formaldehyde resin.

9. A method for preparing the long-acting light-controlled sustained-release suspend-emulsion herbicide according to any one of claims 1 to 8, comprising the following steps: putting an emulsifier, a dispersant, a defoamer and water into a high-shear reactor, adding a light-controlled microcapsule herbicide, a structure regulator and an inorganic filler under a shearing state of 500 to 1000 r / min, and continuing the shearing for 30 to 40 minutes. After the shearing is completed, the long-acting light-controlled sustained-release suspend-emulsion herbicide is obtained.

10. A method for preparing the long-acting light-controlled slow-release suspoemulsion herbicide according to any one of claims 1 to 8, comprising the following steps: (1) adding a dispersant and an emulsifier into a stirring tank and stirring them uniformly to prepare an emulsion phase; (2) adding water into a high shear kettle, adding a light-controlled microcapsule herbicide, a structure regulator, an inorganic filler and a defoamer at a speed of 500 to 1000 r / min, and continuing to stir for 30 to 40 minutes after the addition is completed to obtain a suspension; (3) pumping the emulsion phase in step (1) into the suspension in step (2) at a stirring rate of 800 to 1000 r / min, and continuing stirring for 15 to 20 minutes to obtain a long-acting light-controlled slow-release suspoemulsion herbicide.

Images