Novel pesticide suspending agent as well as preparation method and application thereof

Abstract

The invention relates to a novel pesticide suspending agent which comprises 40-70 wt% of illegal cooking oil methyl ester, 30-60 wt% of cashew nut oil, 0-2 wt% of an antioxidant and 0-3 wt% of a thixotropic agent, the ratio of the illegal cooking oil methyl ester to the cashew nut oil is larger than or equal to 1: 1, the antioxidant is tert-butylhydroquinone, the thixotropic agent is one of organic bentonite, hydrogenated castor oil and fumed silica, and the thixotropic agent is one of organic bentonite, hydrogenated castor oil and fumed silica. In conclusion, the condensation point of the pesticide suspending agent can be ensured to be less than or equal to-5 DEG C through synergistic pour point depressing of a hydroxy fatty acid structure; the method has the advantages of being wide in application range, capable of recycling resources, effectively reducing cost, high in product performance stability, small in environmental pollution and suitable for large-scale popularization.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of agricultural planting, and particularly relates to a novel pesticide suspension concentrate and a preparation method and application thereof. BACKGROUND

[0002] The pesticide suspension concentrate (SC) is an environmental protection type which takes water as a continuous phase, disperses the solid pesticide raw material (usually with a particle size of 1-5 microns) which is insoluble in water through wet grinding, and maintains the particle suspension stability by means of an additive system such as a suspending agent, a dispersing agent, an antifreezing agent and the like. The pesticide suspension concentrate has excellent environmental compatibility, use safety, efficacy enhancement and processing convenience, and is widely used in the field of pesticides. The pesticide suspension concentrate with a palm oil derivative compound system mainly relies on dextrin palmitate as a soil conditioner to effectively improve the soil organic matter content, and can eliminate the release of toxic substances from the source and reduce the toxicity to water and non-target organisms by replacing the solvent with a natural oil carrier. However, the pesticide suspension concentrate with a palm oil derivative compound system also has some problems. Firstly, the unmodified palm oil has a condensation point of about 2℃, and is prone to crystallization or gelation in a severe cold environment below-10℃, which can cause blockage of the conveying pipeline, uneven spraying and efficacy attenuation, and seriously affects its use in northern areas. Moreover, the hydroxyl value and viscosity need to be adjusted during use, which increases the economic cost to a certain extent.

[0003] In order to improve the low-temperature performance, some researches turn to the modification scheme of nanotechnology. The surface effect of nano-silicon suspending agent is mainly used to significantly reduce the viscosity of the system and improve the fluidity under-15℃ conditions. Although these nano-silicon suspending agents can improve the fluidity, they still have the problems of ecological toxicity risk of silicon particles enrichment in soil and high economic cost, which limit the use range of the pesticide suspension concentrate with a palm oil derivative compound system.

[0004] Therefore, there is an urgent need for a novel pesticide suspension concentrate and a preparation method and application thereof to solve the problems of increased economic cost, easy failure in an environment below-10℃, limited use range and easy ecological toxicity risk of the existing pesticide suspension concentrate with a palm oil derivative compound system. SUMMARY

[0005] In view of the above, the application provides a novel pesticide suspension concentrate and a preparation method and application thereof, which can solve the technical problems of increased economic cost, easy failure in an environment below-10℃, limited use range and easy ecological toxicity risk.

[0006] In order to achieve the above technical purposes, the application adopts the following specific technical solutions: A new pesticide suspension agent, comprising 40-70wt% of gutter oil methyl ester, 30-60wt% of cashew oil, 0-2wt% of antioxidant and 0-3wt% of thixotropic agent, the ratio of gutter oil methyl ester to cashew oil is ≥1:1, and the antioxidant is t-butyl hydroquinone.

[0007] Further, the thixotropic agent uses one of organic bentonite, hydrogenated castor oil and fumed silica, and the total addition amount of functional additives including the antioxidant and the thixotropic agent is ≤5%.

[0008] Further, the pesticide suspension agent is synergistically decongealed by hydroxy fatty acid structure, and the congealing point of the pesticide suspension agent is ≤-5℃.

[0009] As shown in Figure 1 A preparation method of a new pesticide suspension agent, comprising the following steps: S1, acid-catalyzed transesterification pretreatment, take the formula amount of cashew oil and put it in the reaction kettle for mild acid-catalyzed transesterification treatment, then mix the treated modified cashew oil methyl ester with the untreated gutter oil methyl ester in a ratio of ≥1:1 at 50-60℃, and then add the antioxidant as needed and dissolve it thoroughly; S2, shear emulsification treatment, slowly add the preheated oil phase to the preheated water phase under good stirring, start the high shear device, and shear at 8000-10000rpm for 5-15 minutes at 50-55℃ to form a uniform coarse emulsion / suspension, then add the formula amount of thixotropic agent to the emulsion system as needed and stir appropriately to obtain a well-dispersed mixed solution; S3, aging and filtration at low temperature, reduce the mixed solution obtained in step S2 to -5℃, keep it at -5℃ for 12 hours, then filter through a filter device pre-cooled to 0℃ or below to complete the preparation of the pesticide suspension agent.

[0010] Further, the cashew oil in step S1 is subjected to acid-catalyzed transesterification pretreatment, and the gutter oil methyl ester is directly used.

[0011] Further, in step S1, the formula amount of cashew oil is placed in the reaction kettle for mild acid-catalyzed transesterification treatment, after the treatment, the acid catalyst and short-chain alcohol are added, and the stirring reaction is carried out under inert atmosphere protection for 1-3h, then neutralization, water washing and dehydration drying are carried out, then the cashew oil is cooled to below 80℃, and the antioxidant in the formula is added and dissolved thoroughly.

[0012] Further, in step S2, the water phase is prepared by adding water, water-soluble dispersant, wetting agent, antifreeze and preservative into a premix tank, then heated to 50-55℃ and stirred to dissolve.

[0013] Further, the thixotropic agent is pre-prepared with the complex oil phase or propylene glycol into a homogeneous paste in a separate container at a shearing speed of 2000-4000 rpm and maintained at 50-55°C, and then the thixotropic agent pre-gel is slowly added into the mixed emulsion system, and continues to be sheared at a medium speed for 5-10 minutes to ensure the uniform dispersion of the thixotropic agent and the formation of a network structure, and then the remaining water is added to make up the volume, and slowly cooled to 40-45°C while maintaining appropriate stirring.

[0014] Further, in step S3, the mixed liquid is reduced to -5°C by stepwise cooling, first reduced to 4°C at a speed of ~1°C / min, and then reduced to -5°C at a speed of ~0.5°C / min, and the filtered clear liquid in step S3 is recovered to room temperature at a speed of 2-5°C / h while maintaining low-speed stirring during the recovery process.

[0015] The application of a novel pesticide suspension agent as described above in a severe cold environment below -10°C.

[0016] The above technical solution can also bring the following beneficial effects: 1、The present application provides a novel pesticide suspension agent, which provides low-temperature fluidity by using waste oil methyl ester, realizes high-value utilization of waste oil through esterification regeneration process, and forms a complex with metal ions through the hydroxyl group -OH generated by cashew nut oil, thereby enhancing the interfacial activity and synergistically reducing the freezing point, so that the freezing point is reduced to below -5°C, the oxidation induction period is prolonged by using an antioxidant, the rheological property is adjusted by modifying bentonite with a thixotropic agent to prevent stratification, thereby effectively reducing the freezing point of the pesticide suspension agent, expanding its application range, and constructing a nano-silicon system with strong cold storage stability, the stability is higher than ≥90%, and the added functional additives do not damage the stability of the system, the biodegradability is significantly improved and is higher than 80%, and the system has the advantages of wide application range, no ecological toxicity pollution, resource recycling and cost reduction.

[0017] 2、The present application provides a novel pesticide suspension agent, which is prepared by acid-catalyzed ester exchange pretreatment, significantly improves the methanol recovery rate to 98%, reduces VOC emissions, dynamically mixes by shear emulsification, avoids local crystallization, makes the particle size D90 less than 5 microns, eliminates microcrystalline nuclei by low-temperature aging, and improves the cold storage stability, and has the advantages of simple preparation method, stable product, small environmental pollution, reduced production cost and suitability for large-scale promotion. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The flowchart of the preparation method of the novel pesticide suspension agent is provided. DETAILED DESCRIPTION

[0019] The present application is described in detail by specific embodiments below, and other advantages and effects of the present application can be easily understood by those skilled in the art from the disclosure of the specification. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. The present application can also be implemented or applied by other different specific embodiments, and various modifications or changes can be made to the details in the specification based on different views and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0020] It should be noted that the various aspects of the embodiments described below are within the scope of the appended claims. It should be apparent that the aspects described herein can be embodied in a wide variety of forms and that any specific structure and / or function described herein is merely illustrative. Based on the present disclosure any aspect described herein can be implemented independently of any other aspect and various examples of implementations commencing with any aspect can be understood by those skilled in the art from the present disclosure. For example, an apparatus can be implemented and / or a method can be practiced using any number of the aspects set forth herein. In addition, the scope of the application is intended to encompass any or all implementations of the aspects described herein.

[0021] It should also be noted that the drawings provided in the following embodiments are only schematic and are intended to provide the basic understanding of the present application. In the drawings, only the components related to the present application are shown, not the number, shape and size of the components as implemented, and the shape, number and proportion of each component can be arbitrarily changed in actual implementation, and the layout of the components can also be more complex.

[0022] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, one skilled in the art will understand that the aspects described can be practiced without these specific details. Embodiment 1

[0023] A new type of pesticide suspension agent, comprising 60 g of methylester of drain oil and 40 g of cashew oil, a preparation method thereof, comprising the following steps: S1, acid-catalyzed transesterification pretreatment, take 40g cashew oil in the reaction kettle for mild acid-catalyzed transesterification treatment, after treatment, add acid catalyst and short chain alcohol, under the protection of inert atmosphere, stir for 1-3h, then neutralize, wash with water and dry, then cool the cashew oil to below 80℃, then mix the treated 60g modified cashew oil methyl ester with untreated gutter oil methyl ester in a ratio of ≥1:1 at 50-60℃ to obtain a composite oil phase, and fully dissolve; S2, shear emulsification treatment, first prepare the water phase by adding water, water-soluble dispersant, wetting agent, antifreezing agent and preservative to the premix tank, then heat to 50-55℃, stir and dissolve, under good stirring, slowly add the preheated oil phase to the preheated water phase, start the high shear device, high speed shear at 8000-10000rpm for 5-15 minutes at 50-55℃ to form a uniform coarse emulsion / suspension; S3, aging and filtration at low temperature, the mixture obtained in step S2 is cooled to -5℃ in steps, first cooled to 4℃ at a rate of ~1℃ / min, keep for 2 hours, then cooled to -5℃ at a rate of ~0.5℃ / min, keep aging at -5℃ for 12 hours, then filter through a filter device pre-cooled to 0℃ below, then the clear liquid after filtration is restored to room temperature at a rate of 2-5℃ / h, and low speed stirring is maintained during the recovery process to complete the preparation of the pesticide suspension concentrate. Example 2

[0024] A new type of pesticide suspension concentrate, comprising 50g gutter oil methyl ester, 48g cashew oil and 2g antioxidant, its preparation method comprises the following steps: S1, acid-catalyzed transesterification pretreatment, take 48g cashew oil in the reaction kettle for mild acid-catalyzed transesterification treatment, after treatment, add acid catalyst and short chain alcohol, under the protection of inert atmosphere, stir for 1-3h, then neutralize, wash with water and dry, then cool the cashew oil to below 80℃, add 1g antioxidant in the formula for fully dissolving, then mix the treated modified cashew oil methyl ester with untreated 50g gutter oil methyl ester in a ratio of ≥1:1 at 50-60℃ to obtain a composite oil phase, add the remaining antioxidant 1g according to the formula, fully dissolve; S2, shear emulsification treatment is carried out, first, the water phase is prepared by adding water, water-soluble dispersing agent, wetting agent, antifreeze, preservative into a premix tank, then heated to 50-55℃, dissolved by stirring, under good stirring, the preheated oil phase is slowly added into the preheated water phase, start high shear equipment, high speed shear at 8000-10000 rpm for 5-15 minutes at 50-55℃, form uniform coarse emulsion / suspension, then the thixotropic agent is pre-gelatinized with complex oil phase or propylene glycol in a separate container to form a homogeneous paste, maintain 50-55℃ under the shear speed of 2000-4000 rpm, then the thixotropic agent pre-gelatinized is slowly added into the mixed emulsion system, continue to shear at medium speed for 5-10 minutes, ensure the thixotropic agent is uniformly dispersed and start to form network structure, then add the remaining water to constant volume, slowly cool to 40-45℃, while maintaining appropriate stirring, get the dispersed mixed liquid; S3, aging filtration is carried out at low temperature, the mixed liquid obtained in step S2 is reduced to -5℃ by stepwise cooling, first reduced to 4℃ at ~1℃ / min, keep 2 hours, then reduced to -5℃ at ~0.5℃ / min, keep aging at -5℃ for 12 hours, then filter through a filter device pre-cooled to 0℃ below, then the filtrate after filtration is recovered to room temperature at the speed of 2-5℃ / h, and low speed stirring is maintained during the recovery process to complete the preparation of the pesticide suspension concentrate. Example 3

[0025] A new type of pesticide suspension concentrate, comprising 70g of drain oil methyl ester, the preparation method thereof comprises the following steps: S1, take 70g of drain oil methyl ester as oil phase for standby; S2, shear emulsification treatment is carried out, first, the water phase is prepared by adding water, water-soluble dispersing agent, wetting agent, antifreeze, preservative into a premix tank, then heated to 50-55℃, dissolved by stirring, under good stirring, the preheated oil phase is slowly added into the preheated water phase, start high shear equipment, high speed shear at 8000-10000 rpm for 5-15 minutes at 50-55℃, form uniform coarse emulsion / suspension; S3, aging filtration is carried out at low temperature, the mixed liquid obtained in step S2 is reduced to -3℃ by stepwise cooling, keep aging at -3℃ for 12 hours, then filter through a filter device pre-cooled to 0℃ below, then the filtrate after filtration is recovered to room temperature at the speed of 2-5℃ / h, and low speed stirring is maintained during the recovery process to complete the preparation of the pesticide suspension concentrate.

[0026] The existing palm oil derivative prepared as a comparative example, and then the pesticide suspension of example 1, example 2, example 3 and comparative example, respectively, carry out the condensation point data comparison, laser particle size instrument test and pesticide efficacy test, through the condensation point data detection method reaction EC50 value, through the laser particle size instrument test and the strength distribution of the suspension, through the pesticide efficacy test to determine the protective effect of pesticide suspension on aphids, the above can be obtained from the pesticide suspension of example 1 is very suitable for-15℃ environment, its EC50 value is reduced by 20%, the condensation point is-6.2℃ (ASTM D97), the suspension rate is 92% after cold storage, the pesticide suspension of example 2, the condensation point is-5.5℃, the oxidation induction period is prolonged from 1.2h to 3.6h, the aphid control effect is improved by 15%, the condensation point of the pesticide suspension of example 3 is-3℃, the suspension rate is 68% after cold storage for 7d, compared with example 4, the low temperature stability and efficacy are also improved to a certain extent, in short, the present application has the advantages of wide application range, resource recycling, cost reduction, stable product, less environmental pollution and large-scale promotion.

[0027] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A novel pesticide suspension concentrate characterized in that: The compound oil phase comprises 40-70wt% of gutter oil methyl ester, 30-60wt% of cashew oil, 0-2wt% of antioxidant and 0-3wt% of thixotropic agent, the ratio of the gutter oil methyl ester to the cashew oil is greater than or equal to 1:1, and the antioxidant is t-butyl hydroquinone.

2. A novel pesticide SC as claimed in claim 1, wherein: The thixotropic agent is one of organic bentonite, hydrogenated castor oil and fumed silica, and the total addition amount of the functional additives including the antioxidant and the thixotropic agent is less than or equal to 5%.

3. A novel pesticide SC as claimed in claim 2, wherein: The pesticide suspension agent is synergistically de-condensed through the hydroxy fatty acid structure, and the condensation point of the pesticide suspension agent is less than or equal to -5℃.

4. A process for the preparation of the novel pesticide suspension concentrate as claimed in claim 1, characterized in that, The method comprises the following steps: S1, acid-catalyzed ester exchange pretreatment is performed, the formula amount of cashew oil is weighed and placed in a reaction kettle for mild acid-catalyzed ester exchange treatment, then the treated modified cashew oil methyl ester is uniformly mixed with untreated gutter oil methyl ester at a ratio of greater than or equal to 1:1 at 50-60℃, a compound oil phase is obtained, an antioxidant is added according to needs and is fully dissolved; S2, shear emulsification treatment is performed, the preheated oil phase is slowly added into the preheated water phase under good stirring, a high shear device is started, high-speed shearing is performed at 8000-10000rpm for 5-15 minutes at 50-55℃, a uniform coarse emulsion / suspension is formed, the formula amount of thixotropic agent is added into the emulsification system according to needs, and appropriate stirring is performed, and a well-dispersed mixed liquid is obtained; S3, aging and filtration are performed at low temperature, the mixed liquid obtained in step S2 is reduced to -5℃, is kept at -5℃ for 12 hours, and then is filtered through a filter device pre-cooled to below 0℃, and the preparation of the pesticide suspension agent is completed.

5. The method for preparing a novel pesticide suspension as described in claim 4, characterized in that: In the step S1, the cashew oil is subjected to acid-catalyzed ester exchange pretreatment, and the gutter oil methyl ester is directly used.

6. The method for preparing a novel pesticide suspension as described in claim 5, characterized in that: In the step S1, the formula amount of cashew oil is weighed and placed in a reaction kettle for mild acid-catalyzed ester exchange treatment, after the treatment, an acid catalyst and a short-chain alcohol are added, stirring reaction is performed under inert atmosphere protection for 1-3h, then neutralization water washing and dehydration drying are performed, then the cashew oil is cooled to below 80℃, and the antioxidant in the formula is added and fully dissolved.

7. The method for preparing a novel pesticide suspension as described in claim 6, characterized in that: In the step S2, the water phase is prepared by adding water, water-soluble dispersant, wetting agent, antifreeze, preservative into a premixing tank, and then heated to 50-55℃ and stirred and dissolved.

8. The method for preparing a novel pesticide suspension as described in claim 7, characterized in that: In the step S2, the thixotropic agent is pre-prepared into a homogeneous paste with the compound oil phase or propylene glycol in a separate container, maintained at 50-55℃ under a shearing speed of 2000-4000rpm, then the thixotropic agent pre-gel is slowly added into the mixed emulsification system, continues to be sheared at medium speed for 5-10 minutes to ensure that the thixotropic agent is uniformly dispersed and starts to form a network structure, then the remaining water is added to constant volume, and slowly cooled to 40-45℃ while keeping appropriate stirring.

9. The method for preparing a novel pesticide suspension as described in claim 8, characterized in that: In the step S3, the mixed liquid is reduced to -5℃ in a stepwise cooling manner, first reduced to 4℃ at a speed of ~1℃ / min, kept at 4℃ for 2 hours, then reduced to -5℃ at a speed of ~0.5℃ / min, and the clear liquid after filtration in the step S3 is recovered to room temperature at a speed of 2-5℃ / h, and kept stirring at low speed during the recovery process.

10. The use of the novel pesticide suspending agent of claim 1 in extremely cold environments below -10°C.

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