Preparation method and application of dendritic block polyether surfactant

Abstract

The invention discloses a preparation method and application of a dendritic block polyether surfactant, and relates to the technical field of polyether surfactants. The invention relates to a preparation method of a dendritic block polyether surfactant, which comprises the following steps: (1) mixing pentaerythritol, a glycidyl ether compound and a catalyst A, heating, stirring and mixing, and carrying out heat preservation reaction to obtain a reaction product; (2) adding a catalyst B into the reaction system in the step (1), adjusting the temperature of the system, introducing nitrogen to replace air in the reaction system, and carrying out aging reaction after feeding is finished; and heating, maintaining the pressure of the system at 0.25-0.3 MPa, adding ethylene oxide, and continuing the aging reaction after the feeding is finished, thereby obtaining the dendritic block polyether surfactant. According to the invention, epoxypropane, ethylene oxide and pentaerythritol are adopted to form a tree-shaped high-performance block polyether surfactant, so that the problems that the emamectin benzoate water suspending agent is easy to be subjected to Ostwald ripening during sanding, easy to separate out during heat storage, easy to grow and the like are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of polyether surfactants, in particular to a preparation method and application of a tree-like block polyether surfactant. Background Art

[0002] As the global population continues to grow and per capita arable land continues to decline, chemical pesticides are crucial tools for ensuring food security and world peace, and humanity's rigid demand for pesticides remains strong. Pesticide surfactants are essential additives in the processing and use of pesticide formulations.

[0003] Since the advent of organic pesticides, with the diversification of pesticide formulations and improvements in performance, pesticide surfactants have also developed towards a multi-variety, serialized approach to meet the processing needs of different pesticide types and formulations. In these new pesticide formulations, simply using common surfactants as wetting agents, dispersants, emulsifiers, and defoamers is no longer sufficient to meet performance requirements. Therefore, the development of surfactants with strong emulsification, good dispersibility, enhanced adsorption capacity, and improved safety has become a major development direction for pesticide surfactants. As pesticides gradually move towards water-based and greener formulations, block polyethers, with their unique properties, can be used as dispersants and emulsifiers in environmentally friendly formulations such as EW, SC, SE, OD, and WG. Block polyethers are important nonionic surfactants, and their performance is closely related to their molecular structure, which can be controlled by molecular weight, the ratio of ethylene oxide to propylene oxide, and the block structure. Block polyethers are mainstream products from foreign companies, while high-performance block polyethers are rare in China.

[0004] Dendrimers represent a significant milestone in the development of macromolecular chemistry. With the continued maturation of synthetic methods, research on dendrimers has rapidly advanced, gradually shifting from synthesis and property studies to functionalization and application research.

[0005] Dendrimers possess a compact, symmetrical structure, high branching, nanoscale dimensions, and a refined three-dimensional structure. Their size, shape, and volume can be controlled at the molecular level. The regularity and uniformity of their structure further enhance the relationship between structure and performance. The structure and characteristics of dendrimers contribute to their unique properties: excellent compatibility, low bulk and solution viscosities, a unique hydrodynamic radius, and ease of modification. With increasing research, their unique properties have garnered significant interest, with applications in catalysis, surfactants, nanocomposites, pharmaceuticals, microelectronics, liquid crystal materials, and more.

[0006] As surfactants, dendrimers differ from traditional surfactants in their structure. As generations increase, their structure gradually approaches a spherical shape, and products of different branching generations all possess a certain degree of surface activity. Dendrimers possess hydrophilic surface groups and a hydrophobic interior. They are single macromolecules linked by covalent bonds. As generations increase, the functional groups on the molecular surface become increasingly dense, containing a large number of active groups that strongly adsorb to the oil-water interface.

[0007] Pentaerythritol has a relatively high melting point (262°C), making it impossible to produce pentaerythritol polyether surfactants directly. It also has difficulty reacting with ethylene oxide or propylene oxide, requiring a suitable production process to overcome these difficulties. Traditional production processes use hot water to dissolve pentaerythritol and then synthesize polyether polyols. Due to the low solubility of pentaerythritol in water, a large amount of alcohol-water must be added, and the product must be removed after the reaction is complete. This results in a long production cycle, high energy consumption, and the generation of large amounts of wastewater. Water reacts with propylene oxide to produce some propylene glycol polyether, which affects product functionality and quality stability. Furthermore, existing technologies use solvents to dissolve pentaerythritol, requiring the subsequent recovery of solvents and catalysts. This results in a long reaction cycle, is environmentally unfriendly, and affects the quality of the polyether surfactants.

[0008] In view of the shortcomings of the existing technology, a preparation method and application of a high-performance dendritic block polyether surfactant with a simple preparation process and no need for dehydration or desolvation are provided. Summary of the Invention

[0009] The purpose of the present invention is to provide a preparation method and application of a dendritic block polyether surfactant to solve the problems raised in the prior art.

[0010] To achieve the above object, the present invention provides the following technical solution: a method for preparing a dendritic block polyether surfactant, comprising the following steps:

[0011] Step (1) pentaerythritol, glycidyl ether compound and catalyst A are mixed, heated to 160-200° C., stirred and mixed, and kept warm for 1-2 hours to obtain a reaction product;

[0012] Step (2) Adding catalyst B to the reaction system of step (1), adjusting the system temperature to 100-140° C., introducing nitrogen to replace the air in the reaction system, and vacuum removing for 0.5-1 h; adding propylene oxide, maintaining the system pressure at 0.25-0.3 MPa, and performing aging reaction after the feeding is completed;

[0013] Heat to 140-180° C., maintain the system pressure at 0.25-0.3 MPa, add ethylene oxide, and continue the aging reaction after the feeding is completed to obtain a dendritic block polyether surfactant.

[0014] Furthermore, the molar ratio of pentaerythritol, glycidyl ether compound, propylene oxide, and ethylene oxide is 1:(2-4):(5-30):(5-30);

[0015] Catalyst A is 0.05-0.5% of the total mass of pentaerythritol and glycidyl ether compound;

[0016] The catalyst B is 0.05-0.5% of the total mass of pentaerythritol, glycidyl ether compound, propylene oxide and ethylene oxide.

[0017] Furthermore, the catalyst A is one or a mixture of potassium hydroxide, sodium hydroxide, tetrabutylammonium chloride, triethanolamine, dimethylamine, boron trifluoride etherate, sulfuric acid, phosphoric acid, zinc chloride, aluminum chloride, sodium phthalate, potassium methoxide, sodium methoxide, tripolychlorophosphazene, and polydiphenoxyphosphazene.

[0018] Furthermore, the glycidyl ether compound is one or a mixture of tetradecyl glycidyl ether, dodecyl glycidyl ether, octyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, trihydroxypropane triglycidyl ether, and 3-glycidyloxypropyltrimethoxysilane.

[0019] Furthermore, the catalyst B is one or a mixture of potassium hydroxide, sodium hydroxide, tetrabutylammonium chloride, triethanolamine, dimethylamine, boron trifluoride etherate, sulfuric acid, phosphoric acid, zinc chloride, aluminum chloride, sodium phthalate, potassium methoxide, and sodium methoxide.

[0020] Furthermore, in step (2), the aging reaction conditions after the propylene oxide feeding is completed are: temperature 110-140° C., time 1-1.5 h;

[0021] Furthermore, in step (2), the amount of ethylene oxide fed can be adjusted according to the performance requirements of the target product propoxyethoxy compound, and the reaction can be carried out with different propylene oxide and ethylene oxide addition numbers and different propylene oxide and ethylene oxide addition orders.

[0022] Furthermore, in step (2), after the aging reaction of ethylene oxide, the reaction system is cooled to 70-80° C., and the pH of the system is adjusted to 5-7 using a neutralizer to terminate the reaction.

[0023] In step (2), the aging reaction conditions after the completion of the ethylene oxide feeding are: temperature 160-180° C., time 0.5-1.0 h.

[0024] Furthermore, the neutralizing agent is one or a mixture of acetic acid, aminoacetic acid, aminosulfonic acid, and dodecylbenzenesulfonic acid.

[0025] The invention discloses an application of a dendritic segmented polyether surfactant, wherein the dendritic segmented polyether surfactant is applied to a pesticide dispersible water suspension concentrate.

[0026] Furthermore, the pesticide dispersible water suspension concentrate is prepared by grinding the pesticide suspension concentrate with zirconium beads. The specific preparation method is as follows:

[0027] The pesticide suspension concentrate and zirconium beads are mixed in a mass ratio of 1:(1.2-1.5), and ground to obtain a pesticide dispersible water suspension concentrate.

[0028] Furthermore, the pesticide suspension comprises the following components: by mass percentage, 4% of the original drug emamectin benzoate, 12% of the original drug indoxacarb, 3% of the dendritic block polyether surfactant, 1.5% of the wetting agent, 1.5% of the dispersant, 2% of the thickener, 3% of the antifreeze agent, 0.5% of the preservative, 0.3% of the defoaming agent, and the remainder is water.

[0029] Furthermore, the grinding process conditions are: time 1-2h, rotation speed 700-900r / min.

[0030] Furthermore, the D90 of the obtained dispersible water suspension particles is below 5 μm.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The present invention uses propylene oxide, ethylene oxide, and pentaerythritol to form a dendritic, high-performance segmented polyether surfactant. The dendritic polyether is dispersed in all directions, resulting in lower surface tension and critical micelle concentration. The dendritic, high-performance segmented polyether surfactant has hydrophilic surface groups and a hydrophobic interior. The functional groups on the molecular surface are densely packed, and the molecule has a large number of cavities inside, which can encapsulate pesticide molecules and ensure stable dispersion of pesticide particles.

[0033] 2. The active ingredient of emamectin benzoate is low in content, the system has high salinity, high water solubility, complex impurities, and a low melting point. The preparation of aqueous suspension concentrates can lead to problems such as easy Ostwald ripening during sand milling, easy precipitation during hot storage, and easy particle size growth. The dendritic high-performance block polyether surfactant of the present invention can solve many of the problems of emamectin benzoate aqueous suspension concentrates. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the structural formula of the dendritic block polyether surfactant prepared in Examples 1-7 of the present invention.

[0035] In the figure, R is C 14 H 29 、C 12 H 25 、C8H 17 、C4H9、Ph、

[0036]

[0037] Both a and b are not 0, and a+b is between 5 and 100. DETAILED DESCRIPTION

[0038] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0039] The following specific implementation method is a laboratory test and can be scaled up;

[0040] The wetting agent is ammonium dodecylbenzenesulfonate, which is sourced from Nanjing Taihua Chemical Co., Ltd.

[0041] The dispersant was phenylethylphenol polyoxyethylene ether phosphate, sourced from Nanjing Taihua Chemical Co., Ltd.

[0042] The thickener is magnesium aluminum silicate, sourced from Shandong Honghe Chemical Co., Ltd.

[0043] The antifreeze agent is ethylene glycol, which is sourced from Shandong Qilin Chemical Co., Ltd.

[0044] The preservative was sodium benzoate, sourced from Shanghai Suke Chemical Co., Ltd.

[0045] The defoaming agent is THIX-288 polyether defoaming agent with a pH value of 5.0-7.0, which is sourced from Yantai Hengxin Chemical Technology Co., Ltd.

[0046] Example 1: A method for preparing a dendritic segmented polyether surfactant, comprising the following steps:

[0047] S1: 136 g of pentaerythritol, 1.8 g of sulfuric acid, and 1080 g of tetradecyl glycidyl ether were mixed, heated to 160° C., stirred evenly, and reacted for 2 h. The reaction was terminated when the epoxy value dropped to 0.01 and did not change any more, thereby obtaining a reaction product;

[0048] S2: 300 g of the reaction product obtained in S1 was mixed with 2.5 g of potassium hydroxide, heated to 100° C., the air in the reactor was replaced by nitrogen, replaced three times, and vacuum removed for 0.5 h. 420 g of propylene oxide was added, the system pressure was maintained at 0.25 MPa, and the reaction was carried out for 1 h. The temperature was raised to 140° C., the system pressure was maintained at 0.25 MPa, 325 g of ethylene oxide was added, the reaction was carried out for 0.5 h, and the reaction was cooled to 80° C. The pH was adjusted to 5 with acetic acid, and the reaction was terminated to obtain a dendritic block polyether surfactant.

[0049] Example 2: A method for preparing a dendritic segmented polyether surfactant, comprising the following steps:

[0050] S1: 136 g of pentaerythritol, 1.8 g of sulfuric acid, and 1080 g of tetradecyl glycidyl ether were mixed, heated to 200° C., stirred evenly, and reacted for 2 h. The reaction was terminated when the epoxy value dropped to 0.01 and did not change any more, thereby obtaining a reaction product;

[0051] S2: 300 g of the reaction product obtained in S1 was mixed with 2.5 g of potassium hydroxide, heated to 140° C., nitrogen was passed through the reactor to replace the air, replaced three times, and vacuum removed for 1 hour; the temperature was raised to 180° C., the system pressure was maintained at 0.3 MPa, 325 g of ethylene oxide was added, and the reaction was carried out for 1 hour; the temperature was lowered to 140° C., 420 g of propylene oxide was added, the system pressure was maintained at 0.3 MPa, the reaction was carried out for 1 hour, and the reaction was cooled to 80° C. The pH was adjusted to 5 with acetic acid, and the reaction was terminated to obtain a dendritic block polyether surfactant.

[0052] Example 3: A method for preparing a dendritic segmented polyether surfactant, comprising the following steps:

[0053] S1: 136 g of pentaerythritol, 2.5 g of phosphoric acid, and 968 g of dodecyl glycidyl ether were mixed, heated to 180° C., stirred evenly, and reacted for 2 h. The reaction was terminated when the epoxy value dropped to 0.01 and did not change any more, thereby obtaining a reaction product;

[0054] S2: 300 g of the reaction product obtained in S1 was mixed with 2.5 g of potassium hydroxide, heated to 120° C., the air in the reactor was replaced by nitrogen, replaced three times, and vacuum removed for 0.7 h. 394 g of propylene oxide was added, the system pressure was maintained at 0.28 MPa, and the reaction was carried out for 1 h. The temperature was raised to 160° C., the system pressure was maintained at 0.28 MPa, 300 g of ethylene oxide was added, the reaction was carried out for 0.7 h, and the reaction was cooled to 80° C. The pH was adjusted to 5 with acetic acid, and the reaction was terminated to obtain a dendritic block polyether surfactant.

[0055] Example 4: A method for preparing a dendritic segmented polyether surfactant, comprising the following steps:

[0056] S1: 136 g of pentaerythritol, 1.5 g of sodium methoxide, and 968 g of octyl glycidyl ether were mixed, heated to 160° C., stirred evenly, and reacted for 2 h. The reaction was terminated when the epoxy value dropped to 0.01 and did not change any more, thereby obtaining a reaction product;

[0057] S2: Take 300g of the reaction product obtained in S1 and 1g of sodium methoxide, mix them, heat to 100°C, replace the air in the reactor with nitrogen, replace three times, vacuum remove for 0.5h, add 400g of propylene oxide, maintain the system pressure at 0.25MPa, and react for 1h; heat to 140°C, maintain the system pressure at 0.25MPa, add 300g of ethylene oxide, react for 0.5h, and cool to 80°C to obtain a tree-like block polyether surfactant.

[0058] Example 5: A method for preparing a dendritic segmented polyether surfactant, comprising the following steps:

[0059] S1: 136 g of pentaerythritol, 2.5 g of dodecylbenzenesulfonic acid, and 600 g of octyl glycidyl ether were mixed, heated to 160° C., stirred evenly, and reacted for 2 h. The reaction was terminated when the epoxy value dropped to 0.01 and did not change any more, thereby obtaining a reaction product;

[0060] S2: 300 g of the reaction product obtained in S1 was mixed with 1 g of triethanolamine and 1.5 g of potassium hydroxide, heated to 100° C., the air in the reactor was replaced by nitrogen three times, and vacuum removed for 1 h. 590 g of propylene oxide was added, the system pressure was maintained at 0.25 MPa, and the reaction was carried out for 1 h. The temperature was raised to 140° C., the system pressure was maintained at 0.25 MPa, 450 g of ethylene oxide was added, the reaction was carried out for 0.5 h, and the reaction was cooled to 80° C. to obtain a dendritic block polyether surfactant.

[0061] Example 6: A method for preparing a dendritic segmented polyether surfactant, comprising the following steps:

[0062] S1: 136 g of pentaerythritol, 1 g of sulfuric acid, and 1200 g of trihydroxypropane triglycidyl ether were mixed, heated to 200° C., stirred evenly, and reacted for 2 h. 186 g of lauryl alcohol was then added and reacted for 2 h. The reaction was terminated when the epoxy value dropped to 0.01 and did not change, thereby obtaining a reaction product.

[0063] S2: 300 g of the reaction product obtained in S1 and 0.8 g of tripolyphosphazene chloride were mixed, heated to 140° C., nitrogen was passed through the reactor to replace the air three times, and vacuum stripping was performed for 1 hour. 340 g of propylene oxide was added, the system pressure was maintained at 0.3 MPa, and the reaction was continued for 1 hour. The temperature was raised to 180° C., the system pressure was maintained at 0.3 MPa, 290 g of ethylene oxide was added, the reaction was continued for 1 hour, and the reaction was cooled to 80° C. to obtain a dendritic block polyether surfactant.

[0064] Example 7: A method for preparing a dendritic segmented polyether surfactant, comprising the following steps:

[0065] S1: 136 g of pentaerythritol, 1 g of sulfuric acid, and 944 g of 3-glycidoxypropyltrimethoxysilane were mixed, heated to 180° C., stirred evenly, and reacted for 2 h. The reaction was terminated when the epoxy value dropped to 0.01 and did not change, thereby obtaining a reaction product;

[0066] S2: 300 g of the reaction product obtained in S1 was mixed with 1.2 g of tripolyphosphazene chloride, heated to 120° C., the air in the reactor was replaced by nitrogen, replaced three times, and vacuum removed for 0.7 h. 420 g of propylene oxide was added, the system pressure was maintained at 0.28 MPa, and the reaction was carried out for 1 h. The temperature was raised to 160° C., the system pressure was maintained at 0.28 MPa, 330 g of ethylene oxide was added, the reaction was carried out for 0.7 h, and the reaction was cooled to 80° C. to obtain a dendritic block polyether surfactant.

[0067] Example 8: The dendrimer-block polyether surfactant obtained in Example 1 was used to prepare a pesticide dispersible aqueous suspension concentrate, comprising the following process:

[0068] The pesticide suspension concentrate and zirconium beads are mixed in a mass ratio of 1:1.5 and ground to obtain a pesticide dispersible water suspension concentrate; the grinding process conditions are: time 1.5 hours, speed 850 r / min.

[0069] Example 9: The dendrimer-block polyether surfactant obtained in Example 2 was used to prepare a pesticide dispersible aqueous suspension concentrate, comprising the following steps:

[0070] The pesticide suspension concentrate and zirconium beads were mixed in a mass ratio of 1:1.5 and ground to obtain a pesticide dispersible water suspension concentrate; the grinding process conditions were: time 1 hour, speed 700 r / min.

[0071] Example 10: The dendritic block polyether surfactant obtained in Example 3 was used to prepare a pesticide dispersible aqueous suspension concentrate, comprising the following process:

[0072] The pesticide suspension concentrate and zirconium beads were mixed in a mass ratio of 1:1.3 and ground to obtain a pesticide dispersible water suspension concentrate; the grinding process conditions were: time 1.5 h, speed 800 r / min.

[0073] Example 11: The dendrimer-block polyether surfactant obtained in Example 4 was used to prepare a pesticide dispersible aqueous suspension concentrate, comprising the following steps:

[0074] The pesticide suspension concentrate and zirconium beads were mixed in a mass ratio of 1:1.4 and ground to obtain a pesticide dispersible water suspension concentrate; the grinding process conditions were: time 1.6 h, speed 750 r / min.

[0075] Example 12: The dendrimer-block polyether surfactant obtained in Example 5 was used to prepare a pesticide dispersible aqueous suspension concentrate, comprising the following steps:

[0076] The pesticide suspension concentrate and zirconium beads were mixed in a mass ratio of 1:1.4 and ground to obtain a pesticide dispersible water suspension concentrate; the grinding process conditions were: time 1.7 h, speed 850 r / min.

[0077] Example 13: The dendrimer-block polyether surfactant obtained in Example 6 was used to prepare a pesticide dispersible aqueous suspension concentrate, comprising the following steps:

[0078] The pesticide suspension concentrate and zirconium beads were mixed in a mass ratio of 1:1.2 and ground to obtain a pesticide dispersible water suspension concentrate; the grinding process conditions were: time 1.8 h, speed 900 r / min.

[0079] Example 14: The dendritic segmented polyether surfactant obtained in Example 7 was used to prepare a pesticide dispersible aqueous suspension concentrate, comprising the following process:

[0080] The pesticide suspension concentrate and zirconium beads were mixed in a mass ratio of 1:1.2 and ground to obtain a pesticide dispersible water suspension concentrate; the grinding process conditions were: time 2 hours, speed 900 r / min.

[0081] Comparative Example 1: Using Example 8 as a comparison, the dendrimer block polyether surfactant was replaced with phenethylphenol polyoxyethylene ether in an equal mass percentage, while other conditions remained unchanged.

[0082] experiment:

[0083] The dendritic block polyether surfactants prepared in Examples 1-7 were tested for surface tension at critical micelle concentration using a BZY-2 surface tension meter at 25° C. using a platinum plate method.

[0084] Surface tension / mN / m Example 1 29.5 Example 2 36.4 Example 3 26.4 Example 4 30.5 Example 5 27.2 Example 6 24.6 Example 7 19.6

[0085] Table 1 Surface tension test results of dendritic block polyether surfactants

[0086] Based on the above data and experiments, we can conclude that the surface tension of conventional surfactants at critical micelle concentration is 30-40 mN / m. The present invention utilizes pentaerythritol and a glycidyl ether compound (both reactants and solvents) to react at 160-200°C to produce a flowable, viscous liquid, overcoming the limitations of direct production of pentaerythritol polyether surfactants. Blocking with propylene oxide and ethylene oxide results in even lower surface tension.

[0087] The performance of the pesticide dispersible aqueous suspension concentrates prepared in Examples 8-14 and Comparative Example 1 was tested;

[0088] Suspension rate test: Follow the GB / T 14825-2006 method for determining pesticide suspension concentrates. Weigh an appropriate amount of sample and place it in a measuring cylinder filled with 250mL of standard hard water. Invert it 30 times within 2 minutes, and then place it in a thermostatic bath filled with 25°C water for 30 minutes. Draw out 9 / 10 (i.e. 225mL) of the suspension from the contents. Do not shake or stir up the sediment in the measuring cylinder. Transfer 25mL of the suspension at the bottom of the measuring cylinder to a culture dish with a known mass of m1, dry it in a 50°C oven to a constant weight, and weigh the mass of the residue m2. The formula for the sample suspension rate is as follows:

[0089] X 悬 =(m1-m2 / m1)*10 / 9*100

[0090] Particle size detection: The average particle size of the prepared suspension was measured using a Malvern laser particle size distribution analyzer;

[0091] High temperature and low temperature stability test: The prepared suspension was stored at 50±2°C and -10±2°C for 14 days, respectively. The active ingredient content before and after high temperature and low temperature storage was detected by liquid chromatography, and the decomposition rate of the active ingredient was calculated;

[0092] Decomposition rate = (content before storage - content after storage) / content before storage × 100%;

[0093] The definition of decomposition rate ≤ 4% is qualified, and the definition of decomposition rate > 4% is unqualified;

[0094] Suspension rate / % D90 Hot storage stability Low temperature stability Example 8 90 4.98 qualified qualified Example 9 82 5.63 qualified qualified Example 10 95 3.31 qualified qualified Example 11 88 4.58 qualified qualified Example 12 92 3.45 qualified qualified Example 13 96 2.94 qualified qualified Example 14 98 2.12 qualified qualified Comparative Example 1 65 6.22 Unqualified Unqualified

[0095] Table 2 Performance tests of suspending agents

[0096]

[0097] Table 3 Appearance of suspension after 14 days of hot storage

[0098] According to the data in the above table, we can clearly draw the following conclusions:

[0099] The pesticide dispersible water suspension concentrates obtained in Examples 8 to 14 were compared with the pesticide dispersible water suspension concentrates obtained in Comparative Example 1. The test results show that:

[0100] The pesticide dispersible water suspension concentrate prepared by the present invention has a higher suspension rate, smaller suspended particle size, and better storage stability at low and high temperatures. It can be seen that the use of the tree-like high-performance block polyether surfactant of the present invention can solve the problems of easy Ostwald ripening of the emamectin salt water suspension concentrate during sand milling, easy precipitation during hot storage, and easy particle size growth.

[0101] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A method for preparing a dendritic block polyether surfactant, characterized in that: The following steps are involved: Step (1) pentaerythritol, glycidyl ether compound and catalyst A are mixed, heated to 160-200° C., stirred evenly, and kept warm for 1-2 hours to obtain a reaction product; Step (2) Adding catalyst B to the reaction system of step (1), adjusting the system temperature to 100-140° C., introducing nitrogen to replace the air in the reaction system, and vacuum removing for 0.5-1 h; adding propylene oxide, maintaining the system pressure at 0.25-0.3 MPa, and performing aging reaction after the feeding is completed; Heat to 140-180° C., maintain the system pressure at 0.25-0.3 MPa, add ethylene oxide, and continue the aging reaction after the feeding is completed to obtain a dendritic block polyether surfactant.

2. The method for preparing a dendritic segmented polyether surfactant according to claim 1, wherein: In step (1), the glycidyl ether compound is one or a mixture of tetradecyl glycidyl ether, dodecyl glycidyl ether, octyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, trihydroxypropane triglycidyl ether, and 3-glycidyloxypropyltrimethoxysilane.

3. The method for preparing a dendritic segmented polyether surfactant according to claim 2, wherein: The molar ratio of pentaerythritol, glycidyl ether compound, propylene oxide and ethylene oxide is 1:(2-4):(5-30):(5-30).

4. The method for preparing a dendritic block polyether surfactant according to claim 1, wherein: In step (2), the aging reaction conditions after the propylene oxide feeding is completed are: temperature 110-140° C., time 1-1.5 h.

5. The method for preparing a dendritic segmented polyether surfactant according to claim 4, wherein: In step (2), the aging reaction conditions after the completion of the ethylene oxide feeding are: temperature 160-180° C., time 0.5-1.0 h.

6. The method for preparing a dendritic segmented polyether surfactant according to claim 5, wherein: In step (2), after the aging reaction of ethylene oxide, the reaction system is cooled to 70-80° C., and the pH of the system is adjusted to 5-7 using a neutralizer to terminate the reaction.

7. The method for preparing a dendritic segmented polyether surfactant according to claim 1, wherein: In step (1), the catalyst A is one or a mixture of potassium hydroxide, sodium hydroxide, tetrabutylammonium chloride, triethanolamine, dimethylamine, boron trifluoride etherate, sulfuric acid, phosphoric acid, zinc chloride, aluminum chloride, sodium phthalate, potassium methoxide, sodium methoxide, tripolychlorophosphazene, and polydiphenoxyphosphazene.

8. The method for preparing a dendritic segmented polyether surfactant according to claim 1, wherein: In step (2), the catalyst B is one or a mixture of potassium hydroxide, sodium hydroxide, tetrabutylammonium chloride, triethanolamine, dimethylamine, boron trifluoride etherate, sulfuric acid, phosphoric acid, zinc chloride, aluminum chloride, sodium phthalate, potassium methoxide, and sodium methoxide.

9. The method for preparing a dendritic segmented polyether surfactant according to claim 6, wherein: The neutralizing agent is one or more of acetic acid, aminoacetic acid, aminosulfonic acid, and dodecylbenzenesulfonic acid.

10. Use of a dendritic segmented polyether surfactant prepared according to the preparation method according to any one of claims 1 to 9, characterized in that: The dendritic segmented polyether surfactant is applied to pesticide dispersible water suspension concentrate.

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