An emulsion-type precise herbicide of isopropyl amine methyl, and a preparation method thereof

Abstract

This invention belongs to the field of chemical herbicide technology, and particularly relates to a water-emulsifiable concentrate of S-metolachlor and its preparation method. The raw material composition of this invention includes S-metolachlor, solvent, emulsifier, co-emulsifier, density enhancer, and viscosity enhancer. The co-emulsifier reduces the particle size of the S-metolachlor oil droplets, the density enhancer increases the density of the aqueous phase, and the viscosity enhancer increases the viscosity of the aqueous phase. Ultimately, this results in S-metolachlor oil droplets that are less prone to flocculation, aggregation, and demulsification, making it a stable emulsion during storage, transportation, and dilution. Furthermore, this invention provides a method for preparing this water-emulsifiable concentrate of S-metolachlor, which uses high-speed stirring and cutting to initially break down the S-metolachlor into sufficiently small oil droplets, providing a good foundation for subsequent anti-flocculation, aggregation, and demulsification effects.

Description

Technical Field

[0001] This invention belongs to the field of chemical herbicide technology, and particularly relates to a water-emulsion type metolachlor herbicide and its preparation method. Background Technology

[0002] S-metolachlor is a selective pre-emergence herbicide, meaning it needs to be sprayed into the soil before weeds sprout. Conversely, if crops have already begun to sprout at this time, S-metolachlor should be sprayed away from the young shoots. Generally, S-metolachlor is suitable for crops such as corn, soybeans, peanuts, cotton, rapeseed, potatoes, and chili peppers.

[0003] On the other hand, most commercially available S-metolachlor is in emulsifiable concentrate form, with a relatively simple composition, generally consisting only of S-metolachlor technical, organic solvent, and emulsifier. The organic solvent is typically toluene or xylene, while the emulsifier forms a stable emulsion after S-metolachlor is diluted with a large amount of water. Without an emulsifier, the S-metolachlor technical and water would be insoluble and separate into layers, with S-metolachlor generally in the lower layer.

[0004] In addition, compared with another equally common pesticide formulation, water-in-oil emulsion, the advantages of emulsifiable concentrate formulation mainly include the following two: 1. Its organic solvent components can have a synergistic effect on S-metolachlor technical; 2. It is not in a completely emulsion state during storage and transportation, so the requirements for emulsifiers and emulsification processes are relatively low, and its overall production method is relatively simple.

[0005] However, compared with the newly emerging water-emulsifiable concentrate (WEEC) S-metolachlor herbicide on the market, the biggest drawback of the WEEC S-metolachlor is that, under the premise of requiring the same amount of S-metolachlor technical, the WEEC S-metolachlor will introduce more organic solvents. These organic solvents are toxic to both the environment and crop seedlings.

[0006] Correspondingly, the reason why water-emulsifiable concentrate (WEEC) herbicides like S-metolachlor were not widely adopted in the early stages is due to the high requirements for emulsifiers and emulsification processes. For example, in one WEEC herbicide, if the emulsified oil droplets of S-metolachlor undergo irreversible flocculation, aggregation, and demulsification during storage and transportation, significant separation and insolubility of S-metolachlor and water will occur when the herbicide is diluted with water, greatly affecting the spraying effect of S-metolachlor.

[0007] Among them, flocculation refers to the aggregation of multiple smaller S-metolachlor oil droplets together, making them difficult to separate; coalescence refers to the formation of a larger oil droplet after multiple smaller S-metolachlor oil droplets break through their outer membranes, and this larger oil droplet itself is unstable; and demulsification refers to the complete rupture of the outer membranes of a large number of S-metolachlor oil droplets, causing S-metolachlor to separate directly from the water.

[0008] For example, Chinese invention patent CN104222074A, published on December 24, 2014, discloses a S-metolachlor water-in-oil emulsion and its preparation method, wherein S-metolachlor is 30-50%, solvent is 1-8%, emulsifier is 2-10%, co-emulsifier is 0.5-4%, antifreeze is 1-5%, defoamer is 0.05-0.5%, stabilizer is 1-5%, and deionized water is added to make up to 100%.

[0009] The advantages of the S-metolachlor water-in-oil emulsion in this invention patent are: relatively good stability, simple and easy production process, water as the dispersion medium, replacing expensive and polluting organic solvents, reducing environmental pollution, improving the safety of product production, storage and transportation, and making it a green and environmentally friendly new formulation.

[0010] However, the biggest shortcoming of this metolachlor emulsion in actual use, which is also the technical problem that this invention aims to solve, is: During relatively long-term storage and transportation, the stability of S-metolachlor oil droplets remains insufficient. The aforementioned phenomena such as flocculation, aggregation, and demulsification are still prone to occur. Ultimately, this leads to the formation of a significant insoluble bottom layer when the S-metolachlor emulsion is diluted with water. This bottom layer contains a high concentration of S-metolachlor technical material, resulting in insufficient drug content in the upper layer of the usable emulsion.

[0011] Therefore, in summary, there is an urgent need for a water-emulsion type of S-metolachlor herbicide with more stable oil drop properties, ensuring that the resulting emulsion remains uniform and stable after dilution. Summary of the Invention

[0012] This invention provides a water-emulsion type S-metolachlor herbicide, the raw material composition of which includes S-metolachlor, solvent, emulsifier, co-emulsifier, density enhancer, and viscosity enhancer. The co-emulsifier is used to reduce the particle size of S-metolachlor oil droplets, the density enhancer is used to increase the density of the aqueous phase, and the viscosity enhancer is used to increase the viscosity of the aqueous phase. Ultimately, this makes the S-metolachlor oil droplets less prone to flocculation, aggregation, and demulsification, and it remains a stable emulsion during storage, transportation, and dilution.

[0013] In addition, the present invention also provides a method for preparing the water-emulsion type S-metolachlor herbicide, which uses high-speed stirring and cutting to break down S-metolachlor into oil droplets with sufficiently small particle size from the beginning, providing a good foundation for the subsequent effect of not easily flocculating, agglomerating and demulsifying.

[0014] The technical solution adopted by the present invention to solve the above problems is: a water-emulsion type S-metolachlor herbicide, the raw material composition of which includes S-metolachlor, solvent, emulsifier, and deionized water, and further includes a co-emulsifier, a density improver, and a viscosity improver, wherein the co-emulsifier is used to reduce the particle size of S-metolachlor oil droplets, the density improver is used to increase the density of the aqueous phase, and the viscosity improver is used to increase the viscosity of the aqueous phase.

[0015] In this invention, at least the following three means are used to improve the stability of S-metolachlor emulsion.

[0016] First, the co-emulsifier can adjust the HLB value of the emulsifier to ultimately obtain smaller S-metolachlor oil droplets. The co-emulsifier can be approximated as a chemical "oil droplet cutter".

[0017] Secondly, the density enhancer is used to increase the density of the aqueous phase so that the density of the aqueous phase is similar to that of the S-metolachlor droplets, ensuring that the S-metolachlor droplets achieve a suspension effect. Otherwise, a relatively large number of S-metolachlor droplets would accumulate in the lower part of the aqueous phase, which would easily increase the frequency of flocculation, aggregation and demulsification.

[0018] The term "spermethrin droplets" refers to both the "spermethrin oil droplets" and the "emulsion film".

[0019] Third, the viscosity improver has a similar effect to the density improver. The viscosity improver can slow down the rate at which the S-metolachlor droplets approach each other, increasing the difficulty for them to approach each other, thereby reducing the frequency of droplet flocculation, aggregation and demulsification.

[0020] On the other hand, compared with the relatively coarse S-metolachlor droplets, the relatively smaller droplets have a larger contact angle. When both are accidentally sprayed onto crop seedlings, the former is more hydrophobic and can roll off the seedlings more quickly, greatly reducing its toxic effect on the seedlings, which is crucial.

[0021] A further preferred technical solution is that the solvent is any one of toluene, xylene, or methanol, and the emulsifier is soybean protein, for forming a mechanical protective film on the surface of S-metolachlor oil droplets.

[0022] In this invention, metolachlor is readily soluble in toluene, xylene, or methanol, which is a necessary condition for the latter three to be used as solvents.

[0023] Compared to commonly used polyether emulsifiers and sulfonate emulsifiers, the advantage of soybean protein is that it can form a tough protective film on the surface of S-metolachlor oil droplets, providing mechanical protection when the S-metolachlor oil droplets are subjected to physical impact, thus preventing the oil droplets from being destroyed. Therefore, aggregation and demulsification are relatively difficult to occur.

[0024] A further preferred technical solution is that the co-emulsifier is either glycerol or polyglycerol ester.

[0025] A further preferred technical solution is that the density improver is either sodium chloride or calcium chloride, and the viscosity improver is carboxymethyl cellulose.

[0026] In this invention, the sodium chloride or calcium chloride can also provide antifreeze effect to the aqueous phase, and both of them are excellent inorganic antifreeze agents, which is quite ingenious.

[0027] In addition, the aqueous phase containing carboxymethyl cellulose can increase the difficulty of the movement of S-metolachlor droplets, thereby reducing the probability of flocculation and aggregation, which is very effective.

[0028] On the other hand, increasing the density and viscosity of the aqueous phase are essentially auxiliary means and play a secondary role. The key to stabilizing the S-metolachlor droplets mainly relies on the synergistic effect of soybean protein emulsifier and glycerol or polyglycerol ester co-emulsifier.

[0029] A further preferred technical solution is that the overall diameter of the methyl metolachlor oil droplets and the multi-molecular emulsion film is 2.4-3.0 μm.

[0030] In this invention, it is through the "chemical cutting effect" of the emulsifier, the emulsifying film protection effect of the soybean protein emulsifier, and the sufficient high-speed stirring effect during subsequent mixing and preparation that the droplets of metolachlor can be guaranteed to reach and be stably and continuously maintained within the relatively small particle size range of 2.4-3.0 μm.

[0031] Generally, the existing S-metolachlor emulsion droplets have a particle size of more than 3.5 μm. This common size of S-metolachlor droplets has a natural disadvantage in avoiding harmful physical phenomena such as flocculation, aggregation and demulsification. Moreover, it has greater wettability on crop seedlings and a longer residence time, which results in a relatively greater toxic effect on crop seedlings.

[0032] A further preferred technical solution is that the density of the aqueous phase is 1.12-1.16 g / ml, and the viscosity of the aqueous phase at 20℃ is 5.5-15 cPs.

[0033] A further preferred technical solution is that the raw material composition includes the following components by weight: 50-55 parts of S-metholarin Solvent xylene 2-6 parts Emulsifier: 5-11 parts soy protein 2-3 parts of polyglycerol ester co-emulsifier Density enhancer: 1-4 parts sodium chloride Viscosity improver: 2-5 parts carboxymethyl cellulose 25-35 parts deionized water.

[0034] A water-emulsion type metolachlor herbicide, the preparation method of which includes the following steps in sequence. S1. Preparation of excipients: Add sodium chloride (density improver), carboxymethyl cellulose (viscosity improver), and some deionized water to a conventional mixer and stir to obtain the excipients; S2. Preparation of main ingredients: The main ingredients are prepared by adding metolachlor, xylene solvent, soybean protein emulsifier, polyglycerol ester co-emulsifier, and the remaining deionized water to a high-speed mixer and stirring. S3. Mixing: Add the auxiliary materials to the main materials, and finally obtain the water-emulsion type metolachlor herbicide at the outlet of the high-speed mixer.

[0035] In S1 of the present invention, the amount of deionized water is less than 15% of the total amount, just enough to ensure that sodium chloride and carboxymethyl cellulose can be fully dissolved, as both are relatively soluble in water.

[0036] In S3 of the present invention, the active phase of the auxiliary material is the entire storage and transportation period. Therefore, it is not necessary to mix it evenly with the main material at the beginning. Since the auxiliary material is a liquid, it can be poured in directly at this time, which can save unnecessary stirring operations, ultimately saving energy and improving production efficiency.

[0037] A further preferred technical solution is that, in S1, the stirring speed is 100-200 r / min and the stirring time is 2-5 min.

[0038] In this invention, the stirring operation only needs to quickly dissolve sodium chloride and carboxymethyl cellulose, which are easily soluble in water. Therefore, the stirring speed is within the normal range and does not require excessive energy consumption.

[0039] A further preferred technical solution is that, in S2, the stirring speed is 5000-10000 r / min and the stirring time is 40-50 min.

[0040] In this invention, the stirring operation in S2 is high-speed or ultra-high-speed stirring, which is to physically separate the S-metolachlor oil droplets, so that the size of the subsequent S-metolachlor liquid droplets can be correspondingly smaller, thereby reducing the degree of occurrence of the three harmful phenomena of flocculation, aggregation and demulsification. Detailed Implementation

[0041] The following description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

[0042] Example 1 A water-in-oil emulsion herbicide, comprising the following components by weight: 50 parts of S-metholarin 3 parts of xylene solvent Emulsifier: 6 parts soy protein Two parts of polyglycerol ester co-emulsifier Density enhancer sodium chloride 3 parts Viscosity improver, carboxymethyl cellulose, 2 parts 26 portions of deionized water.

[0043] Among them, the S-metolachlor oil droplets plus the soybean protein emulsion film are S-metolachlor liquid droplets, and the droplet diameter is 2.5-2.9μm.

[0044] In addition, equal weights of the above-mentioned density enhancer, viscosity enhancer, and deionized water were mixed separately to prepare the aqueous phase of the water-emulsion herbicide. The parameters of the aqueous phase were tested, and the results were: aqueous phase density 1.14 g / ml, aqueous phase viscosity at 20℃ 6.4 cPs.

[0045] Finally, the preparation method of this water-in-oil herbicide includes the following steps in sequence: S1. Preparation of excipients: Add sodium chloride (density improver), carboxymethyl cellulose (viscosity improver), and 10 wt% deionized water to a conventional mixer and stir to obtain the excipients; S2. Preparation of main ingredients: The main ingredients are prepared by adding metolachlor, xylene solvent, soybean protein emulsifier, polyglycerol ester co-emulsifier, and the remaining deionized water to a high-speed mixer and stirring. S3. Mixing: Add the auxiliary materials to the main materials, and finally obtain the water-emulsion type metolachlor herbicide at the outlet of the high-speed mixer.

[0046] In S1, the stirring speed is 120 r / min and the stirring time is 3 min.

[0047] In S2, the stirring speed is 6500 r / min and the stirring time is 40 min.

[0048] Example 2 A water-in-oil emulsion herbicide, comprising the following components by weight: 53 samples of S-metholarin 6 parts of solvent toluene Emulsifier: 10 parts soy protein 2 parts of glycerin as a co-emulsifier Density enhancer: 4 parts calcium chloride Viscosity improver, carboxymethyl cellulose, 4 parts 30 parts deionized water.

[0049] Among them, the S-metolachlor oil droplets plus the soybean protein emulsion film are S-metolachlor droplets, and the droplet diameter is 2.6-3.0μm.

[0050] In addition, equal weights of the above-mentioned density enhancer, viscosity enhancer, and deionized water were mixed separately to prepare the aqueous phase of the water-emulsion herbicide. The parameters of the aqueous phase were tested, and the results were: aqueous phase density 1.13 g / ml, aqueous phase viscosity at 20℃ 6.0 cPs.

[0051] Finally, the preparation method of this water-in-oil herbicide includes the following steps in sequence: S1. Preparation of excipients: Add calcium chloride (density improver), carboxymethyl cellulose (viscosity improver), and 10 wt% deionized water to a conventional mixer and stir to obtain the excipients. S2. Preparation of main ingredients: The main ingredients are prepared by adding metolachlor, toluene solvent, soybean protein emulsifier, glycerol co-emulsifier, and the remaining deionized water to a high-speed mixer and stirring. S3. Mixing: Add the auxiliary materials to the main materials, and finally obtain the water-emulsion type metolachlor herbicide at the outlet of the high-speed mixer.

[0052] In S1, the stirring speed is 120 r / min and the stirring time is 5 min.

[0053] In S2, the stirring speed is 6500 r / min and the stirring time is 45 min.

[0054] Example 3 A water-in-oil emulsion herbicide, comprising the following components by weight: 55 parts of S-metholarin 6 parts of solvent toluene Emulsifier: 11 parts soy protein Two parts of polyglycerol ester co-emulsifier Density enhancer: 4 parts calcium chloride 5 parts of viscosity improver carboxymethyl cellulose 35 parts of deionized water.

[0055] Among them, the S-metolachlor oil droplets plus the soybean protein emulsion film are S-metolachlor liquid droplets, and the droplet diameter is 2.6-2.8μm.

[0056] In addition, equal weights of the above-mentioned density enhancer, viscosity enhancer, and deionized water were mixed separately to prepare the aqueous phase of the water-emulsion herbicide. The parameters of the aqueous phase were tested, and the results were: aqueous phase density 1.13 g / ml, aqueous phase viscosity at 20℃ 7.4 cPs.

[0057] Finally, the preparation method of this water-in-oil herbicide includes the following steps in sequence: S1. Preparation of excipients: Add calcium chloride (density improver), carboxymethyl cellulose (viscosity improver), and 10 wt% deionized water to a conventional mixer and stir to obtain the excipients. S2. Preparation of main ingredients: The main ingredients are prepared by adding metolachlor, toluene solvent, soybean protein emulsifier, polyglycerol ester co-emulsifier, and the remaining deionized water to a high-speed mixer and stirring. S3. Mixing: Add the auxiliary materials to the main materials, and finally obtain the water-emulsion type metolachlor herbicide at the outlet of the high-speed mixer.

[0058] In S1, the stirring speed is 120 r / min and the stirring time is 5 min.

[0059] In S2, the stirring speed is 10000 r / min and the stirring time is 50 min.

[0060] Comparative Example 1 The water-emulsion type metolachlor herbicide and its preparation method in this comparative example differ from those in Example 1 in only one aspect, namely the following.

[0061] The raw material composition of this herbicide, excluding viscosity improvers, has a final aqueous phase viscosity of 2.3 cPs at 20°C.

[0062] Comparative Example 2 The water-emulsion type metolachlor herbicide and its preparation method in this comparative example differ from those in Example 1 in only one aspect, namely the following.

[0063] The raw material composition of this herbicide, excluding density enhancers, has a final aqueous phase density of 1.08 g / ml.

[0064] Comparative Example 3 The water-emulsion type metolachlor herbicide and its preparation method in this comparative example differ from those in Example 1 in only the following two aspects.

[0065] The raw material composition of this herbicide does not include density enhancers and viscosity enhancers. The final aqueous phase viscosity at 20°C is 2.1 cPs and the aqueous phase density is 1.07 g / ml.

[0066] Comparative Example 4 The water-emulsion type metolachlor herbicide and its preparation method in this comparative example differ from those in Example 1 in only one aspect, namely the following.

[0067] The emulsifier in the raw material composition of this herbicide is cetearyl alcohol polyether-25.

[0068] Comparative Example 5 The water-emulsion type metolachlor herbicide and its preparation method in this comparative example differ from those in Example 1 in only the following two aspects.

[0069] In the raw material composition of this herbicide, the emulsifier is cetearyl alcohol polyether-25, and in step S2 of the preparation method, the stirring speed is 300 r / min.

[0070] Herbicide property testing In the above 3 examples and 5 comparative examples, 5 herbicide samples were taken from each example, 50 ml each. The six indicators of layering phenomenon, precipitation phenomenon, droplet size (μm), stability after dilution and antifreeze performance were tested and the average value was recorded in the table below.

[0071] Table 1 Results of herbicide property testing

[0072] Herbicide efficacy testing In the above 3 examples and 5 comparative examples, 5 herbicide samples were taken from each example, each 1000ml.

[0073] Forty experimental plots, each with an area of ​​20m², were selected from potato plants that had already sprouted. 2 The above 40 herbicide samples were sprayed separately, and the results were tested based on three indicators: damage to crop seedlings, residual solvent in the soil, and control of annual weeds. The results are recorded in the table below.

[0074] Table 2 Results of herbicide efficacy testing

[0075] From Tables 1 and 2 above, the following conclusions can be drawn.

[0076] Firstly, regarding the stability of herbicides, five parameters are essential: emulsifier, density enhancer, viscosity enhancer, soybean protein emulsifier, and high-speed stirring and shearing of S-metolachlor oil droplets. None can be omitted; otherwise, the herbicide is prone to precipitation during long-term storage and transportation. While a relatively small amount of precipitation does not affect the stability of the emulsion or its spraying effect after thorough dilution, this does not negate the importance of the stable performance of this S-metolachlor herbicide.

[0077] Secondly, among the five parameters mentioned above, the most fundamental and influential one is the high-speed stirring and shearing of S-metolachlor oil droplets. Of course, this method is generally used in the existing preparation methods of S-metolachlor herbicides.

[0078] Third, sodium chloride and calcium chloride, as density enhancers, also have a highly effective antifreeze effect.

[0079] Fourth, the above five parameters can indirectly reduce the degree of flocculation, aggregation, and demulsification of S-metolachlor droplets, ultimately affecting the "damage to crop seedlings," meaning they are less likely to be poisoned. This is because S-metolachlor droplets have relatively small particle sizes, relatively large contact angles, and greater hydrophobicity, allowing them to roll off crop seedlings more quickly, significantly reducing their toxic effects.

[0080] Fifth, the contributions of the above five parameters to improving the hydrophobicity of S-metolachlor droplets are largely similar to the differences in herbicide performance stability. That is, "soybean protein emulsifier and high-speed stirring and shearing of S-metolachlor oil droplets" are the two main factors, while "co-emulsifier, density enhancer, and viscosity enhancer" are the three auxiliary factors with significant effects.

[0081] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various modifications can be made without departing from the spirit of the present invention. These are all non-inventive modifications, and are protected by patent law as long as they fall within the scope of the claims of the present invention.

Claims

1. A water-emulsion type S-metolachlor herbicide, comprising S-metolachlor, solvent, emulsifier, and deionized water, characterized in that: It also includes a co-emulsifier, a density enhancer, and a viscosity enhancer, wherein the co-emulsifier is used to reduce the particle size of S-metolachlor oil droplets, the density enhancer is used to increase the density of the aqueous phase, and the viscosity enhancer is used to increase the viscosity of the aqueous phase. The solvent is xylene, and the emulsifier is soybean protein, used to form a mechanical protective film on the surface of S-metolachlor oil droplets. The co-emulsifier is polyglycerol ester. The density-increasing agent is sodium chloride, and the viscosity-increasing agent is carboxymethyl cellulose. The raw material composition includes the following components by weight: 50-55 parts of S-metholarin Solvent xylene 2-6 parts Emulsifier: 5-11 parts soy protein 2-3 parts of polyglycerol ester co-emulsifier Density enhancer: 1-4 parts sodium chloride Viscosity improver: 2-5 parts carboxymethyl cellulose 25-35 parts deionized water.

2. The water-emulsion type metolachlor herbicide according to claim 1, characterized in that: The overall diameter of the methyl isopropyl hydroxylamine oil droplets and the multimolecular emulsion film is 2.4-3.0 μm.

3. The water-emulsion type metolachlor herbicide according to claim 1, characterized in that: The density of the aqueous phase is 1.12-1.16 g / ml, and the viscosity of the aqueous phase at 20℃ is 5.5-15 cPs.

4. A water-emulsion type metolachlor herbicide as described in claim 1, characterized in that... The preparation method includes the following steps in sequence: S1. Preparation of excipients: Add sodium chloride (density improver), carboxymethyl cellulose (viscosity improver), and some deionized water to a conventional mixer and stir to obtain the excipients; S2. Preparation of main ingredients: The main ingredients are prepared by adding metolachlor, xylene solvent, soybean protein emulsifier, polyglycerol ester co-emulsifier, and the remaining deionized water to a high-speed mixer and stirring. S3. Mixing: Add the auxiliary materials to the main materials, and finally obtain the water-emulsion type metolachlor herbicide at the outlet of the high-speed mixer.

5. The water-emulsion type metolachlor herbicide according to claim 4, characterized in that: In S1, the stirring speed is 100-200 r / min, and the stirring time is 2-5 min.

6. The water-emulsion type metolachlor herbicide according to claim 4, characterized in that: In S2, the stirring speed is 5000-10000 r / min, and the stirring time is 40-50 min.

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