CN113396900A

CN113396900A - Thiodicarb aqueous suspension and preparation method thereof

Info

Publication number: CN113396900A
Application number: CN202110554066.5A
Authority: CN
Inventors: 赵万喜; 王瑞华; 郭学阳; 杨帅; 赵旭; 张文佩; 王晨希; 郝天良; 王建建; 袁延増
Original assignee: Weifang Haibang Chemical Co ltd
Current assignee: Weifang Haibang Chemical Co ltd
Priority date: 2021-05-20
Filing date: 2021-05-20
Publication date: 2021-09-17

Abstract

The invention discloses a thiodicarb water suspending agent and a preparation method thereof, wherein the suspending agent comprises 28.5-31.5% of thiodicarb, 12.1-14.6% of auxiliary agent and the balance of water in percentage by weight. The auxiliary agent comprises a dispersing agent, a thickening agent, an antifreezing agent, a suspension stabilizer, a corrosion and mildew inhibitor, a defoaming agent and a pH regulator. The dispersing agent is a compound mixture of four surfactants, namely sodium dodecyl sulfate, a nonionic toilet copolymer, EO-PO block polyether and maleic acid-acrylic acid copolymer sodium salt. The preparation adopting the components provided by the invention has the advantages of high active component content, good dispersion performance, good dispersion stability of the system and the like; the preparation process provided by the invention has the advantages of strong production continuity, good dispersion effect and high production efficiency, and can be used for rapidly dispersing and dissolving materials; the materials are mixed more uniformly, the product uniformity is strong, and the quality index is more stable.

Description

Thiodicarb aqueous suspension and preparation method thereof

Technical Field

The invention belongs to the technical field of pesticide preparation, and particularly relates to a thiodicarb aqueous suspension and a preparation method thereof.

Background

Thiocarb is a generation of carbamate pesticide with high efficiency, broad spectrum, low toxicity, quick action and systemic property, is one of low toxicity derivatives of methomyl, has insecticidal activity similar to that of methomyl, and has lower toxicity than methomyl. The action mode of the pesticide on pests is that after the active ingredients of the pesticide liquid contact and permeate into acetylcholine receptors of the pests, the active ingredients of the pesticide liquid inhibit esterase activity and then hinder reactivation of conductive substances in nerve fibers of the pests, and finally the pests are poisoned and die. The pesticide is widely used for crops such as cotton, soybean, corn, wheat, vegetables, fruit trees, tea, tobacco, forest and the like, is effective on lepidoptera, coleopteran and dipteran pests, has higher activity on eggs of the lepidopteran pests, is uniformly sprayed by adding water, is effective on various pests such as aphids, cotton bollworms and the like, and can exert remarkable insecticidal effect. According to the statistical data of the Chinese pesticide industry Association, 4 dosage forms of thiodicarb preparation products registered and used in China at present are obtained, and the first wettable powder accounts for 46.8 percent of the total number of the preparation products; secondly, suspending agent accounts for 25 percent of the total amount of the preparation product; the third is water dispersible granules which account for 18.8 percent of the total amount of the preparation product; finally, the suspension seed coating agent accounts for 9.4 percent of the total amount of the preparation product. Therefore, in the registered thiodicarb preparation products at present, the traditional dosage form wettable powder still occupies the dominant position, and the products also comprise 2 products with low content of 25 percent, and the proportion of the novel environment-friendly dosage form suspending agent, the water dispersible granule and other products is still low.

The pesticide suspending agent is one of four environment-friendly formulations recommended by the Food and Agriculture Organization (FAO) of the United nations. In recent years, due to the requirements of environmental protection and food safety, the traditional formulations such as missible oil, powder and the like are gradually eliminated, and environmental-friendly preparations represented by suspending agents and water dispersible granules become the research and development focus of the industry and are the fastest-developing preparations in China at present. The total registered number of the suspending agents in China is the third pesticide formulation (missible oil first, wettable powder second). The suspending agent takes water as a dispersing medium, solid raw medicine which is insoluble or slightly soluble in water is ground by sanding and uniformly dispersed under the action of adding a surfactant and other additives to form a highly suspended and flowable relatively stable liquid-solid system with fine particles (generally the average particle size is less than 5 mu m), and the prepared high-quality suspending agent generally has the advantages of fine particle size (generally 1-3 mu m, average 90% particle size is less than 5 mu m) and high suspension rate (generally more than 90%, and better more than 95%). It does not use any organic solvent, and has no dust generation, and has low toxicity and irritation to human and animals. The dosage form is not flammable, explosive and dust-generating during packaging, storage and transportation. The suspending agent has more advantages than wettable powder, such as no dust, easy mixing, improved suspension rate during dilution, improved wetting, lower packaging volume, safety for operators and users as well as the environment, relatively low cost and high biological efficiency, and has remarkable and durable drug effect compared with wettable powder due to better dispersibility and spreadability, high suspension rate, stronger capability of adhering to the surface of the body and rain wash resistance; compared with missible oil, the emulsion can avoid using a large amount of organic solvent; the thiodicarb aqueous suspension has the characteristics of high suspension rate, small particle size, high drug effect, large active surface, strong permeability, no dust during dosage, low cost and the like, has better dispersibility and spreadability, stronger spreadability and adhesive force on the surface of a plant body, rain wash resistance, obvious and durable drug effect, and thus is an environment-friendly dosage form with good safety, good comprehensive performance and good application prospect. Some work is also carried out on the theoretical research of pesticide suspending agent formulations including thiodicarb suspending agents in China, but the formulation of the thiodicarb suspending agent only has theoretical reference value; chinese patent (publication No. CN103039471B) provides an insecticidal composition containing thiodicarb and dicyclanil, Chinese patent (publication No. CN103004821A) provides an insecticidal composition containing thiodicarb and spinosad, Chinese patent (publication No. CN101213970A) provides an insecticide composition containing thiodicarb active ingredients and application thereof, the patents all mention formulas and operation methods for preparing thiodicarb suspending agents by using the thiodicarb and other pesticide combinations, but most of auxiliaries with different purposes are single formulas and stay in an experimental stage, product analysis indexes and detection results are lacked, the rationality of the process and the formula cannot be judged, and the auxiliary agents can only be used as simple references of the formulas; wangli et al, published in "applied chemistry" 2010 No. 6, a paper "wetting dispersant required by selecting a pesticide suspending agent by a Zeta potential method" put forward that Zeta potential can be used as an index for representing the dispersion performance of the wetting dispersant, and the average particle size of rear particles using a compound wetting dispersant is minimum, the change before and after thermal storage is small, the system achieves the optimal dispersion effect, and the formula of the thiodicarb suspending agent has certain guiding significance; the Liaoke super et al published in the 'Chinese pesticide' 6 th publication paper 'problems frequently occurring in pesticide suspending agents and prevention strategies' of Liaoke super et al propose prevention measures aiming at the problems frequently occurring in pesticide suspending agents, and have certain inspiring effect on the formula for preparing thiodicarb suspending agents; however, in comprehensive consideration, no domestic literature is published so far to provide a preparation process of the thiodicarb suspending agent with excellent quality indexes such as physical stability, chemical stability and the like.

The main problems existing in the preparation of the existing thiodicarb aqueous suspension agent are as follows:

1. the physical stability of the product is poor, water separation, layering, thickening, deposition and caking are easy to occur in storage, the active ingredients of the pesticide are difficult to uniformly disperse, and even the caking can not be poured out of a package, so that the popularization and the use of the suspending agent in agricultural production are seriously influenced;

2. the grain size of the suspending agent is increased greatly during storage, and the quality is rapidly deteriorated;

3. the sand milling is difficult, the uniform slurry preparation difficulty is high during the production, and the flocculation and coalescence are easy to realize;

4. severe foaming, much foam and difficult defoaming;

5. the heat storage stability is poor, the suspending agent is easy to be subjected to austenite curing in the heat storage process, and the particle size is rapidly increased, so that the suspending agent is seriously pasted and solidified; sometimes, the suspending agent is easy to agglomerate and solidify after being placed at normal temperature after being stored thermally, so that the suspending agent cannot adapt to the external environment. These problems are particularly likely to occur when the external environment temperature changes relatively greatly or frequently.

The quality, the product sale and the use effect of the domestic thiodicarb aqueous suspension agent product are seriously restricted by the existence of the problems. With the increasing emphasis on the problems of pesticide pollution and people's concern on the environment, the pesticide has become a hot topic in the field of preparations. Therefore, the physical and chemical properties of the original thiodicarb are fully researched, the influence of the matching of the auxiliary agents (dispersing agent, thickening agent, antifreezing agent, defoaming agent and the like) with different structures, different molecular weights and different physical and chemical properties on the quality indexes of the thiodicarb aqueous suspension is discussed, the thiodicarb aqueous suspension with good suspension property and good thermal storage stability is produced, the risks brought by pesticides and the use thereof are reduced by the innovation of the preparation technology, the healthy development of the industry is promoted, and the win-win of economic benefits and social benefits is realized, so that the method has great significance.

Disclosure of Invention

In order to solve the defects of the prior art, the invention researches and explores the stability problem of the suspending agent, selects proper auxiliary agents and the proportion thereof, and selects and optimizes the types and the dosage of various auxiliary agents through a large amount of experiments to obtain the formula of the aqueous suspending agent with better dispersibility, suspension stability and heat storage stability, thereby forming a new production process. The effect of the invention is realized by the following technical scheme:

the first aspect of the invention is to provide a thiodicarb aqueous suspension agent, which comprises the following components, by weight, 28.5-31.5% of thiodicarb, 12.1-14.6% of an auxiliary agent, and the balance of water.

The auxiliary agent comprises a dispersing agent, a thickening agent, an antifreezing agent, a suspension stabilizer, an antiseptic and mildew-proof agent, a defoaming agent and a pH regulator.

Preferably, the dispersing agent is a compound mixture of four surfactants, namely sodium dodecyl sulfate, a nonionic toilet copolymer, EO-PO block polyether and maleic acid-acrylic acid copolymer sodium salt (polycarboxylic acid sodium salt).

The nonionic toilet copolymer is a polymer prepared by adopting alkylphenol, formaldehyde and ethylene oxide as raw materials through polycondensation, and the specific components used in the invention are Polynonyl phenol polyoxyethylene ether selected from liquid Polynonyl phenol polyoxyethylene ether NP-4, Polynonyl phenol polyoxyethylene ether NP-7, Polynonyl phenol polyoxyethylene ether NP-9 or Polynonyl phenol polyoxyethylene ether NP-10, and more preferably Polynonyl phenol polyoxyethylene ether NP-10.

Preferably, the thickener is selected from the group consisting of xanthan gum, a mixture of magnesium aluminum silicate and carboxymethyl cellulose.

Preferably, the antifreeze is selected from a mixture of ethylene glycol and urea.

Preferably, the suspension stabilizer is selected from the group consisting of polyamide formulations, mixtures of EDTA.

Preferably, the antiseptic and mildew preventive is selected from a mixture of sodium benzoate and 1, 2-benzisothiazolin-3-one (BIT).

Preferably, the defoaming agent is selected from silicone auxiliary agents and C₈-C₁₀Mixtures of fatty alcohol compounds.

Preferably, the pH adjuster is tartaric acid.

Preferably, in the dispersing agent, the dosage of the sodium dodecyl sulfate is 1.3-2.0%, the dosage of the nonionic toilet copolymer is 0.9-1.5%, the dosage of the EO-PO block polyether is 0.9-2.3%, the dosage of the maleic acid-acrylic acid copolymer sodium salt is 0.8-1.6%, and the total dosage of four dispersing agent materials is 4.8-6.9%. .

Preferably, the xanthan gum is 0.01-1.0%, the magnesium aluminum silicate is 0.2-1.2%, the carboxymethyl cellulose is 0.01-1.0%, and the total amount of the three materials is 0.2-3%.

Preferably, in the antifreeze, the dosage of the ethylene glycol is 3-5%, the dosage of the urea is 0.1-1.5%, and the total dosage of the two materials is 3.5-5.5%;

in the suspension stabilizer, the dosage of the polyamide preparation is 0.05-0.3%, the dosage of the EDTA is 0.05-0.5%, and the total dosage of the two materials is 0.1-0.5%;

in the antiseptic and mildew preventive, the dosage of sodium benzoate is 0.02-0.1%, the dosage of 1, 2-benzisothiazolin-3-one is 0.08-0.15%, and the total dosage of the two materials is 0.08-0.2%;

in the defoaming agent, the dosage of the organic silicon additive is 0.2-0.8%, the dosage of the C8-C10 fatty alcohol compound is 0.1-0.6%, and the total dosage of the two materials is 0.3-0.9%;

the amount of tartaric acid used as pH regulator is 0.05-0.1%; finally, water is used for complementing to 100 percent.

As a second aspect of the present invention, there is provided a method for preparing a thiodicarb suspension concentrate, comprising the steps of:

step 1, batching: accurately metering various material components according to the material proportion;

step 2, primary water dissolution: adding water accounting for 60 percent of the total amount into a dissolving kettle, adding one or two of suspension stabilizer, thickening agent, antiseptic and mildew preventive, pH regulator, defoaming agent and antifreezing agent which are metered at one time under the stirring condition, observing the dissolving condition of the material by a sight glass of the dissolving kettle, and keeping the material for later use after the material is dissolved to obtain a one-time mixed material;

step 3, secondary water dissolution: adding the metered active compound thiodicarb, secondary water (the rest water accounting for 40 percent of the total amount) and other auxiliary agents into a mixing kettle, stirring and mixing, fully mixing for 15-30 minutes, adding the primary mixed material in the dissolving kettle in the step 2 into the dissolving kettle, and continuously stirring and mixing for 10-15 minutes to obtain a secondary mixed material;

step 4, shearing: transferring the secondary mixed material obtained in the step 3 to a high-shear emulsifying machine, and shearing and crushing the secondary mixed material into micron-level particles;

step 5, sanding;

step 6, standing, sampling, analyzing and inspecting;

and 7, packaging.

Preferably, the suspension stabilizer, the thickening agent, the preservative and mildew inhibitor, the pH regulator, the defoaming agent and the antifreezing agent added in the step 2 are EDTA, xanthan gum, carboxymethyl cellulose, sodium benzoate, tartaric acid, an organic silicon assistant and urea respectively.

Preferably, in step 5, the first sanding process is: sanding the particles obtained in the step (4) for 30-80 minutes by using a horizontal sand mill, wherein the rotating speed of the horizontal sand mill is 1100 r/min, and the grain size is not more than 5 mu m after sampling and analyzing; then carry out the second sanding process: and sanding for 20-60 minutes by using a horizontal sand mill, wherein the rotating speed of the horizontal sand mill is 1440 rpm, and the grain size of the sampled and analyzed grains after sanding is not more than 3 mu m.

According to the technical scheme, according to the physicochemical properties of thiodicarb and the research experience of similar products, the important functions of a dispersing agent in the preparation process and the use are fully considered, and the compounding of four surfactants including sodium dodecyl sulfate, a nonionic toilet copolymer, EO-PO block polyether and maleic acid-acrylic acid copolymer sodium salt (polycarboxylic acid sodium salt) is selected and determined by combining the requirements of the solid dispersion degree and the suspension stability of a suspension system. The small molecular weight sodium lauryl sulfate mainly functions as a wetting agent. The EO-PO block polyether serving as a macromolecular block copolymer not only can play a role in blocking and dispersing, but also has good emulsifying property, so that the interfacial energy of a dispersed phase can be effectively reduced, the emulsifying effect of original drug particles is improved, and the stability of a suspension system is greatly improved. The polycarboxylic acid is matched with the block polyether, so that creaming can be effectively prevented, and the grain size increase caused by austenite curing is prevented; the specific molecular structure of the nonionic toilet copolymer is helpful for ensuring the good dispersion stability of the thiodicarb aqueous suspension agent.

According to the technical scheme provided by the invention, the viscosity of the thickener adjusting system is adjusted by adopting the three components of xanthan gum, magnesium aluminum silicate and carboxymethyl cellulose, compared with a monomer thickener, the composite thickener has obvious advantages, and after multiple thickeners are compounded, the composite thickener can play a complementary role, expand the application range and improve the use function, so that the pesticide water suspending agent is thickened, and meanwhile, the pesticide water suspending agent is endowed with excellent mechanical property and storage stability.

The technical scheme provided by the invention fully considers the physical and chemical properties and application of thiodicarb, and reasonably matches the selected and used auxiliary agents (including a dispersing agent, a wetting agent, a binder and a disintegrating agent), so that the defect of a single variety of auxiliary agents is avoided; the auxiliary agents are carefully selected and matched, the proportion is reasonable, the chemical properties are stable, the auxiliary agents do not react with each other, the chemical components of the auxiliary agents are not damaged or chemical reaction is not generated when the auxiliary agents are combined with the thiodicarb technical product, and the chemical stability and the physical stability of the preparation are improved.

The technical scheme provided by the invention selects a proper defoaming agent, and the prepared preparation has low surface tension after being sprayed, good wettability on the surface of the target and strong spreading and penetrating abilities, is distributed on the surface of the target in fine particles and is beneficial to improving the drug effect.

The preparation prepared by the technical scheme has the advantages of high active component content, good dispersion performance, good dispersion stability of a system and the like; the process designed by the scheme has strong production continuity, can quickly disperse and dissolve materials, has good dispersion effect and high production efficiency; the production equipment is safe and reliable, the operation and maintenance are simple, the operation is stable, and the installation is simple and convenient. Micronizing, emulsifying, mixing, homogenizing, dispersing, etc. in high-speed shearing emulsifying machine in short time. The water is added into the high-speed shearing emulsifying machine twice, the water is added for the first time, and the water for dissolving the auxiliary agent is added for the second time, so that various materials are mixed more uniformly, the uniformity of the product is strong, and the quality index is more stable.

Compared with the prior art, the invention has the beneficial effects that:

(1) the preparation adopting the components provided by the invention has the advantages of high active component content, good dispersion performance, good dispersion stability of the system and the like;

(2) the preparation process provided by the invention has the advantages of strong production continuity, good dispersion effect and high production efficiency, and can be used for rapidly dispersing and dissolving materials; the production equipment is safe and reliable, the operation and maintenance are simple, the operation is stable, and the installation is simple and convenient; the materials are micronized, emulsified, mixed, uniformly mixed, dispersed and the like in a high-speed shearing emulsifying machine in a short time, so that the preparation efficiency is greatly reduced;

(3) the water is added into the high-speed shearing emulsifying machine twice, the water is added for the first time, and the water for dissolving the auxiliary agent is added for the second time, so that various materials are mixed more uniformly, the uniformity of the product is strong, and the quality index is more stable.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.

FIG. 1 is a flow chart of a preparation method of thiodicarb aqueous suspension provided by the invention.

Detailed Description

For the preparation of pesticide suspensions, the aim is to increase the suspension rate and suspension stability of the formulation and to increase the heat storage stability of the formulation.

In one aspect, the pesticide suspension is a highly dispersed multi-phase complex system whose stability is dependent on a number of factors. Besides the physicochemical properties of the pesticide active ingredient itself (such as physical form, melting point, solubility in water, volatility, hydrolytic stability, chemical stability, light stability, thermal stability, etc.), the factors of the added surfactants (wetting agents, dispersants) and various additives (such as antifreeze agents, thickeners, preservatives, antifoaming agents and other auxiliaries) need to be considered, and the interaction between them has an influence on the stability of the suspension concentrate.

On the other hand, the problem of the storage stability of the suspending agent is always a main problem restricting the development and production of the suspending agent. Pesticide suspensions are not storage stable because the suspension itself is a highly dispersed heterogeneous complex system consisting of many adjuvant ingredients in addition to the active ingredient and the dispersing medium. It is always present in the form of a highly concentrated suspension, which may be chemically unstable during long-term storage, and more frequently is subject to physical stability problems. Most of the poor physical stability of the suspending agent is due to flocculation and aggregation of particles in a dispersed phase, or even aggregation, caused by collisions during brownian motion of the particles, and irreversible aggregation and aggregation caused by van der waals forces between the particles. To improve this, the particles may be provided with a protective layer sufficient to prevent attractive aggregation between the particles, either by an ionic dispersant providing electrostatic repulsion, by a non-ionic dispersant providing steric hindrance, or by a polymeric surfactant dispersant of superior performance.

Aiming at the problems that the existing domestic thiodicarb aqueous suspending agent has poor suspension stability and thermal storage stability, easily generates bubbles in the preparation process, is difficult to eliminate, and has poor physical stability such as water separation, thickening, precipitation and the like in storage, according to (1) Stokes Law (Stokes Law, 1845), the physical stability of the suspending agent in storage is related to factors such as viscosity, density difference, suspended particle size and the like of a preparation; (2) the basic organic chemical structure theory, the structure-determining property of the compound, and the unique amphiphilic molecular structure of the surfactant determine the basic characteristics of the compound, mainly including wetting, soaking, dispersing, emulsifying, solubilizing and the like, wherein the surfactant with the dispersing effect is added into the system to form a uniform and stable suspension. In a suspension system, mutual collision among particles is inevitable, and irreversible flocculation resistance among suspended particles is prevented by the charge of the particles and an adsorption layer formed by the surfactant on the surfaces of the particles, which is the dispersion action principle of the surfactant. Ionic surfactants act due to repulsive forces generated by the electric double layer formed at the particle/solution interface; the nonionic surfactant and the macromolecular dispersant are adsorbed on the surfaces of the original drug particles to form steric hindrance, so that the particles repel each other and aggregation is prevented, and the key for ensuring the storage physical stability of the suspending agent is to select an auxiliary agent reasonably matched with the original drug.

In the invention, a thiodicarb suspending agent preparation is provided, and a dispersing agent, a thickening agent, an antifreezing agent, a suspension stabilizing agent, an antiseptic and mildewproof agent, an antifoaming agent and a pH adjusting agent are selected and prepared.

1. Selection of dispersants

The dispersing agent is a surfactant which can help the particles to be split and dispersed, prevent flocculation and stabilize the particles, is added into the suspending agent, and plays a role in helping the particles to be dispersed and suspended during production and ensures that the dosage form product can be dispersed into a suspension suitable for spraying after being diluted by adding water during use. The dispersant has a strong ability to adsorb on the surface of the particles and provides an electrical repulsive force and a steric barrier to prevent re-aggregation and sedimentation of the particles. The factors to be considered for selecting the dispersing agent are (1) when a large amount of water exists, the dispersing agent does not have the decomposition effect on the raw pesticide and does not promote the decomposition of the raw pesticide; (2) the decomposition is not easy to occur under the acidic and alkaline conditions and water; (3) when the pesticide active ingredient slurry is subjected to sand grinding, the particle size is reduced, the low viscosity among particles is kept, and the dispersion and processing are facilitated; (4) the external surface and the porous surface of the dispersed pesticide active ingredient particles are well wetted; (5) can form stable suspension dispersion. If the selected dispersing agent is not suitable for the physicochemical properties of the thiodicarb, the developed suspending agent has poor stability, and the phenomena of agglomeration and bottom formation usually occur in the storage process, thereby influencing the quality of products and the exertion of the drug effect. The wetting dispersant of the pesticide water suspending agent is mainly anionic and nonionic surfactant monomer or anionic and nonionic surfactant compound, and the thickness of the adsorption layer can be changed by the mixture of the anionic and nonionic surfactant monomer and the anionic and nonionic surfactant monomer, so that the physical stability of the suspending agent is improved.

Repeated experiments and comparison prove that the four surfactants including the sodium dodecyl sulfate, the nonionic toilet copolymer, the EO-PO block polyether and the maleic acid-acrylic acid copolymer sodium salt (polycarboxylic acid sodium salt) are compounded. The dispersing ability of the surfactant depends on the molecular weight and the characteristics of the hydrophobic groups, and in general, a hydrophobic surfactant with a large molecular weight diffuses slowly to the surface of particles, but has strong adsorption ability, is not easy to transfer from the surface, and can provide long-term stability of the pesticide preparation. The maleic acid-acrylic acid copolymer sodium salt has large molecular weight, small sensitivity to ions, pH value, temperature and the like in a suspension system, high dispersion stability, difficult sedimentation and flocculation, remarkably reduced viscosity of the dispersion system and better fluidity at high solid content; the EO-PO block polyether is a nonionic surfactant, belongs to a macromolecular block copolymer, and has a good steric hindrance effect. The mechanism of stabilization is generally considered that the block dispersant adsorbs at the interface of the dispersed phase particles and forms a dense adsorption layer. The compact adsorption layer on the particle meeting face of the dispersed phase can generate steric hindrance effect on the further approach of the particle meeting face, thereby maintaining the dispersion stability of the water suspension system. Structurally, the macromolecular chain has two groups, one is an oily group which can be strongly adsorbed on dispersed pesticide particles, and the other is a hydrophilic group with good hydration, and the groups have good flexibility and generate good repulsion with each other, so that the good dispersion stability of the pesticide suspension concentrate is ensured. The macromolecular block copolymer not only can play a role in blocking and dispersing, but also has good emulsifying property, can effectively reduce the interfacial energy of a dispersed phase, improves the emulsifying effect of original drug particles, and greatly improves the stability of a suspension system. The polycarboxylic acid is compounded with the block polyether, so that creaming can be effectively prevented, and the grain size increase caused by austenite curing can be prevented. Sodium lauryl sulfate primarily functions as a wetting agent. The nonionic comb-type dispersing agent is adsorbed on the surfaces of thiodicarb particles through an anchoring group, so that the surfaces of the particles can be charged to generate an electric double layer around the particles, the electrostatic repulsive force is increased, the hydrophilic solvation branched chain extends into water to form steric hindrance, the particles are separated, and the stability of the particles is improved. The application of the nonionic toilet copolymer with the structure in the production of pesticide suspending agents is not seen at home.

2. Selection of thickeners

Thickeners, also known as gelling agents, can increase the viscosity or consistency of the formulation, maintain a uniform, stable suspension or emulsion, or form a gel. The pesticide water suspending agent is a coarse dispersion system, is easy to settle original drug particles under the action of gravity, belongs to an unstable suspension system, and has the problem of suspension stability. According to the classical Stoke sedimentation formula, the addition of a thickening agent to the aqueous suspension agent is required to obtain a suitable viscosity (250-1000cp) to reduce sedimentation of the particles. The thickening agent belongs to a rheological additive, has specific rheological property, and is an additive capable of improving the physical characteristics of the suspending agent and improving the viscosity of the suspending agent. In the preparation process of the suspending agent, the viscosity of the material can be improved and adjusted, and the dispersion of pesticide particles and the like is facilitated; during the storage process, it can prevent the sedimentation and agglomeration of various media. The thickener not only can thicken the pesticide aqueous suspension agent, but also can endow the pesticide aqueous suspension agent with excellent mechanical property and storage stability, although the addition amount is not large, the thickener can greatly improve the viscosity or consistency of the product, and becomes an indispensable component of the pesticide aqueous suspension agent. Proper selection and use of thickeners is important to address the variety of rheological issues that arise in the manufacture, storage and use of pesticide suspensions. The main requirements of the pesticide on the suspension thickener are: (1) the product is mixed with the stock solution, has good intermiscibility, and does not influence the appearance color and the function of the product; (2) the viscosity of the suspension is improved, the sedimentation of the raw materials during the storage period is avoided, and the raw materials are not easy to delaminate and flocculate. The consistency of the product before and after production is kept; (3) the thickening function is strong, a small amount of thickening agent is added, and a large amount of thickening agent improves rheological property; (4) good water resistance, alkali resistance, good suspension property, uniform mixing property, good thickening property and low cost; (5) has good solubility and viscosity characteristics, non-thermal gelation property and high shear viscosity. The thickening agent is also called as food gum or dextrin, the molecular structure of the thickening agent is provided with a plurality of hydrophilic groups such as hydroxyl, carboxyl, amino, carboxylate radical and the like, and the groups are highly dispersed in water in a molecular state after hydration with water molecules to form a single-phase uniform dispersion system with high viscosity. Due to the special molecular structure of the thickening agent, the thickening agent plays roles in thickening, stabilizing, suspending, improving gel structure, improving structure and the like under different coordination conditions. The product is found in research: the use of a single thickener often has significant drawbacks. Compared with a monomer thickener, the composite thickener has obvious advantages, and can play a complementary role, expand the application range and improve the use function after a plurality of thickeners are compounded. The invention selects three components of xanthan gum, magnesium aluminum silicate and carboxymethyl cellulose as the thickening agent to regulate the viscosity of the system, thereby reducing the sedimentation of thiodicarb technical particles in the storage process and improving the suspension stability of the thiodicarb water suspending agent.

3. Selection of antifreeze

Because of the presence of a significant amount of water in the suspension formulation, the addition of an anti-freeze agent increases the freeze-thaw capacity that the suspension formulation withstands and increases the low temperature stability of the suspension formulation in order to prevent freezing during storage and transportation due to weather damage to the performance of the formulation. The ethylene glycol and the propylene glycol are generally selected as the antifreezing agent to meet the requirements. Through a plurality of experiments, the use of ethylene glycol and urea as the antifreezing agent is determined.

4. Suspension stabilizer

Suspension stabilizers are generally used in suspensions, are substances which keep the fine particles in suspension, have a high degree of dispersion, a large surface area, a high degree of adsorption, influence on the surrounding water and on the surrounding other particles, do not settle rapidly, have a thickening effect on the suspension, and are additives which prevent the components of the suspension from settling. The traditional suspending agents mainly used in the past are based on chlorides, such as sodium chloride (NaCl) and ammonium chloride (NH)₄Cl), it was experimentally confirmed that two materials, polyamide formulation and EDTA, were used as suspension stabilizers.

5. Antiseptic and mildew-proof agent

The common pesticide water suspending agent is added with antiseptic and mildew inhibitor (also called pesticide preparation protective agent), common acetaldehyde aqueous solution, polyformaldehyde, sodium citrate, sodium salicylate, sorbitol and the like. The thiodicarb is stable between the pH value of 3-6 and does not decompose, and the sodium benzoate is an acidic preservative, so that the preservative effect is good under acidic conditions, and meanwhile, the decomposition of the thiodicarb can be effectively prevented, and the stability of the thiodicarb is maintained; the 1, 2-benzisothiazolin-3-one (BIT) has good stability under an acidic condition, can effectively prevent thiodicarb from decomposing, and simultaneously has industrial sterilization and anticorrosion performances, and sodium benzoate and the 1, 2-benzisothiazolin-3-one (BIT) are used as an anticorrosion mildew inhibitor according to the physicochemical characteristics of the thiodicarb.

6. Selection of antifoam agent

Because the suspending agent is added with the surfactant, the dispersion disc rotating at high speed in the production process can easily bring the surrounding air into the dispersion system to form tiny bubbles; dilution of the product necessarily produces foam. The addition of a defoaming agent is necessary because it causes various inconveniences to the process, affects not only viscosity, metering and product packaging, but also reduces production efficiency and affects user use and drug effect. According to experience, the organic silicon additive and C are selected by combining the physical and chemical properties of the thiodicarb₈-C₁₀Fatty alcohol compounds also act as defoamers. The organosilicon adjuvant in the formula has stronger surface activity than that of a common nonionic surfactant, can effectively reduce the surface tension of a solution, the critical surface tension of a plant is an important parameter for the application of pesticides, and when the surface tension of a liquid medicine is less than the critical surface tension of a certain plant, the pesticide can be wetted and spread on the surface of the plant. The organic silicon variety can reduce the contact angle between the spraying solution and the leaf surface, thereby increasing the coverage of spraying. It can also improve the adhesive force of pesticide fog drops on plant leaves, and possibly reduce the pesticide spraying amount; at the same time, the amount of water required to cover a particular leaf surface is reduced as more liquid medicine adheres to the target.

7. pH modifier selection

This is an important means of ensuring the chemical stability of the active ingredients in the formulation. The thiodicarb is stable in summer under neutral medium conditions and slightly acidic conditions, and slowly decomposes when the pH value exceeds 9, so that the pH adjusting medium is added to meet the requirement of the original drug on the pH value of the medium, and the active ingredient content and the storage stability are prevented from being influenced by the decomposition or other chemical reactions of the original drug. The use of tartaric acid as a pH modifier was experimentally determined.

The present invention will now be described in detail with reference to specific examples, it should be noted that the following examples are intended to illustrate the present invention only and should not be construed as limiting the scope of the present invention, and that many insubstantial modifications and adaptations of the invention by those skilled in the art based on the teachings of the present invention described above will still fall within the scope of the present invention. In addition, the starting materials and equipment used are those which are commercially available and customary in the art, unless otherwise stated; unless otherwise specified, the metering parameters are mass or weight contents.

Example 1

Step 1, batching: the raw materials are accurately metered according to the following weight ratio of the materials.

The main components are as follows: 30% of thiodicarb original drug (100% of the total content);

dispersing agent: sodium dodecyl sulfate 1.3%, nonionic toilet copolymer 1.5% of polynonyl phenol polyoxyethylene ether (NP-10), EO-PO block polyether 0.9%, and maleic acid-acrylic acid copolymer sodium salt 1.6%;

thickening agent: 0.06% of xanthan gum, 0.8% of magnesium aluminum silicate and 0.5% of carboxymethyl cellulose;

an antifreezing agent: 3.2% of ethylene glycol and 2.1% of urea;

suspension stabilizer: polyamide preparation 0.1%, EDTA 0.1%;

and (3) antiseptic and mildew preventive: sodium benzoate 0.02%, BIT 0.06%;

defoaming agent: 0.5% of organic silicon additive and C₈-C₁₀0.4% of fatty alcohol compound;

pH regulator: tartaric acid 0.08%.

Step 2, primary water dissolution: adding water accounting for 60 percent of the total amount into a dissolving kettle, sequentially adding EDTA, xanthan gum, sodium benzoate, tartaric acid, carboxymethyl cellulose, an organic silicon auxiliary agent and urea which are measured under the stirring condition, observing the dissolving condition of the materials from a sight glass of the dissolving kettle, and obtaining a primary mixture after the materials are dissolved;

step 3, secondary water dissolution: adding the metered raw pesticide, secondary water (the residual water accounting for 40 percent of the total amount) and other additives which are not dissolved in the water into a mixing kettle for fully mixing, continuously stirring the materials in the mixing kettle in a rotating way through special stirring in the kettle to continuously generate a new interface, cutting, compressing and folding the materials to stir and mix the materials. Mix for 15 minutes.

And 4, adding the dissolved materials from the dissolving kettle to the mixing kettle to obtain a primary mixture in the step 2, and continuously mixing for 15 minutes.

And 5, adding the primary mixture, mixing, adding the material into a high-shear emulsifying machine by virtue of gravity and the suction of the high-shear emulsifying machine, cutting the material in a shear gap by virtue of processes of strong shearing, dispersion, impact, turbulent flow and the like generated between a rotor and a stator which rotate at a high speed, and quickly crushing the material into micron-level particles.

Step 6, sanding the particles obtained in the step 5 for 40 minutes by using a horizontal sand mill, wherein the rotating speed of the horizontal sand mill is 1100 r/min, and the sampled and analyzed particle size after sanding is not more than 5 microns; then the second sanding process: and sanding for 50 minutes by using a horizontal sand mill, wherein the rotating speed of the horizontal sand mill is 1440 rpm, and the grain size of a sample after sanding is not more than 3 mu m. Placing in a standing tank, sampling, analyzing various indexes, inspecting, and packaging.

The results of the tests on the prepared products are shown in Table 1.

Results of testing thiodicarb suspension concentrates prepared in Table 1

Thiodicarb decomposition rate (analysis result of preparation-analysis result after heat storage) ÷ analysis result of preparation × 100%.

The suspension rate was measured as follows: reference is made to GB/T14825-2006;

low temperature stability according to the pesticide low temperature stability determination method GB/T19137-2003; the national standard stipulates that: the suspension rate and wet sieve test indexes are qualified when tested under specified test conditions.

Heat storage stability, as per 2.3 of GB/T19136-2003; and (3) measuring results: after heat storage, the relative decomposition rate of thiodicarb is less than or equal to 5.0%, the relative decomposition rate of methomyl is less than or equal to 0.25%, the suspension rate is greater than or equal to 90.0%, and the pH value, the pourability and the wet sieve test all meet the standard requirements, so that the heat storage stability is qualified.

According to the analysis result of the thermal storage stability, after thermal storage, the relative decomposition rate of thiodicarb is 2.99% (less than or equal to 5.0%), the relative decomposition rate of methomyl is 0% (less than or equal to 0.25%), the suspension rate is 96.2% (more than or equal to 90.0%), and the pH value, the pourability and the wet sieve test all meet the standard requirements, so the thermal storage stability is qualified.

And (4) combining the analysis result of the cold storage stability, and after cold storage, all detection indexes including the suspension percentage and the wet sieve test indexes are qualified, so that the cold storage stability is qualified.

Example 2

1. The ingredients are measured according to the following material proportion.

30% of thiodicarb original drug (100% of the total content);

dispersing agent, sodium dodecyl sulfate 1.3%, nonionic toilet copolymer, polyoxyethylene nonylphenol ether (NP-7) 1.5%, EO-PO block polyether 1.2%, and sodium salt of maleic acid-acrylic acid copolymer 0.8%;

thickening agent including xanthan gum 0.08%, magnesium aluminum silicate 0.8%, and carboxymethyl cellulose 0.4%;

an antifreezing agent: 3.8% of ethylene glycol and 1.1% of urea;

suspension stabilizer: polyamide preparation 0.08%, EDTA 0.13%;

and (3) antiseptic and mildew preventive: sodium benzoate 0.06%, BIT 0.09%;

defoaming agent: 0.4% of organic silicon additive and C₈-C₁₀0.3% of fatty alcohol compound;

pH regulator: tartaric acid 0.06%.

2. Dissolving in primary water

Adding water accounting for 60 percent of the total amount into the dissolving kettle, sequentially adding the measured EDTA, xanthan gum, sodium benzoate, tartaric acid, carboxymethyl cellulose, organic silicon auxiliary agent and urea under the stirring condition, and observing the dissolving condition of the materials from a sight glass of the dissolving kettle. The materials are dissolved for standby;

3. preparation of

Adding the metered raw pesticide, secondary water (the residual water accounting for 40 percent of the total amount) and other additives which are not dissolved in the water into a mixing kettle for fully mixing, continuously stirring the materials in the mixing kettle in a rotating way through special stirring in the kettle to continuously generate a new interface, cutting, compressing and folding the materials to stir and mix the materials. Mixing for 12 minutes, adding primary water of the dissolved materials from the dissolving kettle into the mixing kettle, and continuing to mix for 20 minutes. After the primary water is added and mixed, the materials are added into the high-shear emulsifying machine by means of gravity and the suction of the high-shear emulsifying machine for emulsification, and the materials are cut in a shearing seam through the processes of strong shearing, dispersion, impact, turbulent flow and the like generated between a rotor and a stator which rotate at high speed, and are rapidly crushed into micron-level particles. The materials sequentially enter a first sanding procedure and a second sanding procedure through a high-shear emulsifying machine, sanding is carried out for 50 minutes and 60 minutes respectively, and the two sanding procedures are detected step by step in the middle; placing in a standing tank, sampling, analyzing various indexes, inspecting, and packaging. The results of the tests on the prepared products are shown in Table 2.

Table 2 shows the results of the thiodicarb suspension concentrate test

According to the analysis result of the thermal storage stability, after thermal storage, the relative decomposition rate of thiodicarb is 3.58% (less than or equal to 5.0%), the relative decomposition rate of methomyl is 0% (less than or equal to 0.25%), the suspension rate is 96.7% (more than or equal to 90.0%), and the pH value, the pourability and the wet sieve test all meet the standard requirements, so the thermal storage stability is qualified.

Example 3

1. The ingredients are measured according to the following material proportion.

30% of thiodicarb original drug (100% of the total content);

dispersing agent: 2% of sodium dodecyl sulfate, 0.9% of non-ionic toilet copolymer Polynonyl phenol polyoxyethylene ether (NP-9), 1.3% of EO-PO block polyether and 1.1% of maleic acid-acrylic acid copolymer sodium salt;

thickening agent: 0.05% of xanthan gum, 1.2% of magnesium aluminum silicate and 1.1% of carboxymethyl cellulose;

an antifreezing agent: 4% of ethylene glycol and 0.5% of urea;

suspension stabilizer: polyamide preparation 0.12%, EDTA 0.11%;

and (3) antiseptic and mildew preventive: sodium benzoate 0.05%, BIT 0.08%;

defoaming agent: 0.3% of organic silicon additive and C₈-C₁₀0.1% of fatty alcohol compound;

pH regulator: tartaric acid 0.07%.

2. Dissolving in primary water

3. preparation of

Adding the metered raw pesticide, secondary water (the residual water accounting for 40 percent of the total amount) and other additives which are not dissolved in the water into a mixing kettle for fully mixing, continuously stirring the materials in the mixing kettle in a rotating way through special stirring in the kettle to continuously generate a new interface, cutting, compressing and folding the materials to stir and mix the materials. Mixing for 25 min, adding the primary water of the dissolved material from the dissolving kettle to the mixing kettle, and continuing mixing for 12 min. After the primary water is added and mixed, the materials are added into the high-shear emulsifying machine by means of gravity and the suction of the high-shear emulsifying machine for emulsification, and the materials are cut in a shearing seam through the processes of strong shearing, dispersion, impact, turbulent flow and the like generated between a rotor and a stator which rotate at high speed, and are rapidly crushed into micron-level particles. The materials sequentially enter a first sanding procedure and a second sanding procedure through a high-shear emulsifying machine, sanding is carried out for 60 minutes and 40 minutes respectively, and the two sanding procedures are detected step by step in the middle; placing in a standing tank, sampling, analyzing various indexes, inspecting, and packaging. The results of the tests on the prepared products are shown in Table 3.

Table 3 test results of thiodicarb suspension concentrates

According to the analysis result of the thermal storage stability, after thermal storage, the relative decomposition rate of thiodicarb is 3.05% (less than or equal to 5.0%), the relative decomposition rate of methomyl is 0% (less than or equal to 0.25%), the suspension rate is 96.6% (more than or equal to 90.0%), and the pH value, the pourability and the wet sieve test all meet the standard requirements, so the thermal storage stability is qualified.

Example 4

1. The ingredients are measured according to the following material proportion.

30% of thiodicarb original drug (100% of the total content);

dispersing agent: sodium dodecyl sulfate 1.9%, nonionic toilet copolymer 1.1% of polynonyl phenol polyoxyethylene ether (NP-4), EO-PO block polyether 2.3%, and maleic acid-acrylic acid copolymer sodium salt 1.6%;

thickening agent: 0.02% of xanthan gum, 1.9% of magnesium aluminum silicate and 0.3% of carboxymethyl cellulose;

an antifreezing agent: 4.1 percent of glycol and 0.2 percent of urea;

suspension stabilizer: polyamide preparation 0.06%, EDTA 0.08%;

and (3) antiseptic and mildew preventive: sodium benzoate 0.08%, BIT 0.1%;

defoaming agent: 0.6% of organic silicon additive and C₈-C₁₀0.2% of fatty alcohol compound;

pH regulator: tartaric acid 0.06%.

2. Dissolving in primary water

3. preparation of

Adding the metered raw pesticide, secondary water (the residual water accounting for 40 percent of the total amount) and other additives which are not dissolved in the water into a mixing kettle for fully mixing, continuously stirring the materials in the mixing kettle in a rotating way through special stirring in the kettle to continuously generate a new interface, cutting, compressing and folding the materials to stir and mix the materials. Mixing for 10 min, adding the primary water of the dissolved material from the dissolving kettle to the mixing kettle, and continuing to mix for 25 min. After the primary water is added and mixed, the materials are added into the high-shear emulsifying machine by means of gravity and the suction of the high-shear emulsifying machine for emulsification, and the materials are cut in a shearing seam through the processes of strong shearing, dispersion, impact, turbulent flow and the like generated between a rotor and a stator which rotate at high speed, and are rapidly crushed into micron-level particles. The materials sequentially enter a first sanding procedure and a second sanding procedure through a high-shear emulsifying machine, sanding is carried out for 70 minutes and 30 minutes respectively, and the two sanding procedures are detected step by step in the middle; placing in a standing tank, sampling, analyzing various indexes, inspecting, and packaging. The results of the tests on the prepared products are shown in Table 4.

Table 4 test results of thiodicarb suspension concentrates

According to the analysis result of the thermal storage stability, after thermal storage, the relative decomposition rate of thiodicarb is 1.94% (less than or equal to 5.0%), the relative decomposition rate of methomyl is 0% (less than or equal to 0.25%), the suspension rate is 95.6% (more than or equal to 90.0%), and the pH value, the pourability and the wet sieve test all meet the standard requirements, so the thermal storage stability is qualified.

Example 5

1. Ingredients

The raw materials are measured according to the following material proportion:

thiodicarb (100% discount) 30%

Dispersing agent: 1.8% of sodium dodecyl sulfate, 1.1% of nonionic toilet copolymer, 2.1% of EO-PO block polyether and 1.5% of maleic acid-acrylic acid copolymer sodium salt;

thickening agent: 0.03% of xanthan gum, 1.5% of magnesium aluminum silicate and 0.5% of carboxymethyl cellulose;

an antifreezing agent: 3.5 percent of glycol and 0.8 percent of urea;

suspension stabilizer: polyamide preparation 0.3%, EDTA 0.09%;

and (3) antiseptic and mildew preventive: sodium benzoate 0.08%, BIT 0.15%;

defoaming agent: 0.3% of organic silicon additive and C₈-C₁₀0.5% of fatty alcohol compound;

pH regulator: tartaric acid 0.05%.

2. Dissolving in primary water

3. preparation of

Adding the metered raw pesticide, secondary water (the residual water accounting for 40 percent of the total amount) and other additives which are not dissolved in the water into a mixing kettle for fully mixing, continuously stirring the materials in the mixing kettle in a rotating way through special stirring in the kettle to continuously generate a new interface, cutting, compressing and folding the materials to stir and mix the materials. Mixing for 20 min, adding the primary water from the dissolving kettle to the mixing kettle, and mixing for 15 min. After the primary water is added and mixed, the materials are added into the high-shear emulsifying machine by means of gravity and the suction of the high-shear emulsifying machine for emulsification, and the materials are cut in a shearing seam through the processes of strong shearing, dispersion, impact, turbulent flow and the like generated between a rotor and a stator which rotate at high speed, and are rapidly crushed into micron-level particles. The materials sequentially enter a first sanding procedure and a second sanding procedure through a high-shear emulsifying machine, sanding is carried out for 65 minutes and 55 minutes respectively, and the two sanding procedures are detected step by step in the middle; placing in a standing tank, sampling, analyzing various indexes, inspecting, and packaging. The results of the tests on the prepared products are shown in Table 5.

Results of testing thiodicarb aqueous suspension prepared in Table 5

According to the analysis result of the thermal storage stability, after thermal storage, the relative decomposition rate of thiodicarb is 2.27% (less than or equal to 5.0%), the relative decomposition rate of methomyl is 0% (less than or equal to 0.25%), the suspension rate is 96.1% (more than or equal to 90.0%), and the pH value, the pourability and the wet sieve test all meet the standard requirements, so the thermal storage stability is qualified.

Through the application of the examples 1-5, the product prepared by the process of the invention has qualified indexes, which shows the stability, operability and repeatability of the process technology, and is reasonable in technology.

The product has acquired pesticide registration certificate (registration certificate number PD20090688) issued by the national agricultural rural ministry, and the certificate issuing time is 2018, 10 months and 27 days.

Comparative example 1: the same raw materials and proportions as in example 5 were used, with the following differences:

2. dissolving in primary water

Adding water accounting for 60 percent of the total amount into the dissolving kettle, sequentially adding all the metered thickening agent, the antifreezing agent, the suspension stabilizer, the anticorrosion and mildewproof agent, the defoaming agent and the pH regulator under the stirring condition, and observing the dissolving condition of the materials from a sight glass of the dissolving kettle. The materials are dissolved for standby;

3. preparation of

The metered raw drug, secondary water (the remaining water accounting for 40% of the total amount), and other additives which are not dissolved in the water are added into a mixing kettle to be fully mixed, and the rest of the operation is the same as that of the example 5. The results of the tests on the obtained products are shown in Table 6.

Results of testing thiodicarb suspension concentrates prepared in Table 6

According to analysis results, the thickening agent, the antifreezing agent, the suspension stabilizer, the corrosion and mildew inhibitor, the defoaming agent and the pH regulator are added at one time, three indexes of a wet sieve test, pourability and lasting foam amount in the prepared product are all unqualified, and the suspension rate is only 91.4%, which is mainly because: after the components of the thickening agent, the antifreezing agent, the suspension stabilizer, the antiseptic and mildew preventive, the defoaming agent and the pH regulator are completely dissolved in water, when the components are subjected to common sanding with thiodicarb technical product and other auxiliary agents, due to the fact that the physical and chemical properties of the components are different from the expansion degree of the components after the components are dissolved in water, local mixing of all the materials is uneven, and the product is unqualified. Therefore, the product is meaningless to be analyzed for hot storage stability and cold storage stability.

Comparative example 2: the same production process as in example 5 was used, except that:

the total amount of the dispersing agent in the material ratio is not changed (6.5 percent in total),

sodium dodecyl sulfate 1.8%

Maleic acid-acrylic acid copolymer sodium salt 4.7%

Two dispersants, namely nonionic toilet copolymer and EO-PO block polyether are not used

The operation was the same as in example 5. The results of the tests on the obtained products are shown in Table 7.

Results of testing thiodicarb aqueous suspensions prepared in Table 7

From the above analysis results, it can be seen that the suspending agent product prepared without using two dispersants, namely, the nonionic toilet copolymer and the EO-PO block polyether, has unacceptable specifications. The main reasons are: when only sodium dodecyl sulfate and sodium maleate-acrylate copolymer are used as the dispersing agent, the dispersing agent is easy to fall off from the surface of the thiodicarb due to the strong solvation effect of the two active agents, particularly the sodium maleate-acrylate copolymer, and meanwhile, the hydrophilic chains are easy to tangle to cause flocculation, so that the dispersing effect is reduced. The lauryl sodium sulfate has low molecular weight, low viscosity and weak bonding force with the thiodicarb surface, and is easy to generate 'bridging' coalescence, so that the dispersion stability is reduced, and the product is unqualified. Therefore, the product is meaningless to be analyzed for hot storage stability and cold storage stability.

Comparative example 3

The same production process as in example 5 was used, except that:

nonionic comb copolymer 3.2%

EO-PO block polyether 3.3%

Two dispersants of sodium dodecyl sulfate and sodium salt of maleic acid-acrylic acid copolymer are not used

The procedure was the same as in example 5. The results of the tests on the obtained products are shown in Table 8.

Results of testing thiodicarb aqueous suspension prepared in Table 8

From the above analysis results, it can be seen that the suspension product prepared without using two dispersants, sodium lauryl sulfate and sodium salt of maleic acid-acrylic acid copolymer, has unacceptable specifications. The main reasons are: the low molecular weight sodium dodecyl sulfate mainly plays a role of a wetting agent, the sodium salt solvation effect of the maleic acid-acrylic acid copolymer is strong, and when only the nonionic toilet copolymer HE and the EO-PO block polyether are used as dispersing agents, the particle size increase caused by austenite curing is prevented, but the dispersion stability of the whole system is reduced, and the prepared product is unqualified. Therefore, the product has no meaning for the analysis of storage stability and cold storage stability.

Comparative example 4 the same production process as in example 5 was used, except that:

the suspension stabilizer is changed from polyamide preparation and EDTA into sodium chloride and ammonium chloride. The total amount of sodium chloride and ammonium chloride was constant and remained 0.39%, wherein sodium chloride was 0.15%, and ammonium chloride was 0.24%.

Other raw materials, auxiliary agents and water are unchanged.

The procedure was the same as in example 5. Due to the change of the raw materials, only the suspension rate, the wet sieve test, the pourability and the lasting foam amount of the prepared product are detected, any unqualified product is judged, and other indexes are not checked. The results of the tests on the obtained products are shown in Table 9.

Results of testing thiodicarb aqueous suspensions prepared in Table 9

From the above analysis results, it can be seen that, by using sodium chloride and ammonium chloride instead of the polyamide formulation and EDTA, only two indexes of the wet sieve test and the amount of the permanent foam were qualified, and the suspension rate and the pourability were not qualified. Because the polyamide formulation acts as a high molecular weight polymer, the suspension effect achieved under the same conditions is significantly better than that achieved by using only sodium chloride and ammonium chloride.

Comparative example 5 the same production process as in example 5 was used, except that:

the dosage of the four auxiliary agents of the dispersing agent, the thickening agent, the antifreezing agent and the suspension stabilizer is adjusted, and the specific dosage is as follows: dispersing agent: 2.4% of sodium dodecyl sulfate, 1.9% of nonionic toilet copolymer, 1.7% of EO-PO block polyether and 1.9% of maleic acid-acrylic acid copolymer sodium salt; the total amount is 7.9%

Thickening agent: 0.95% of xanthan gum, 0.15% of magnesium aluminum silicate and 1.05% of carboxymethyl cellulose; the total amount is 3.15%;

an antifreezing agent: 4.9 percent of ethylene glycol and 1.3 percent of urea; the total amount is 6.2%;

suspension stabilizer: polyamide preparation 0.25%, EDTA 0.4%; the total amount is 0.65%;

the feeding amount of other raw medicines and auxiliary agents is unchanged, and the water is supplemented to 100 percent.

Results of testing thiodicarb aqueous suspensions prepared in Table 9

From the analysis results, after the dosages of the dispersing agent, the thickening agent, the antifreezing agent and the suspension stabilizer are increased, only two indexes of a wet sieve test and a lasting foam amount are qualified, and the suspension rate and the dumping property are unqualified. After the use amount of the four auxiliary agents is increased, compared with the material proportion screened under the optimal condition, the matching property among various auxiliary agents is poor, the suspension rate is reduced, the material ash causes poor pouring performance at the bottom of an experimental container, and the residues after washing are excessive.

Comparative example 6 the same production process as in example 5 was used, except that:

the dosage of the four auxiliary agents of the dispersing agent, the thickening agent, the antifreezing agent and the suspension stabilizer is adjusted, and the specific dosage is as follows: dispersing agent: sodium dodecyl sulfate 0.9%, nonionic toilet copolymer 0.8%, EO-PO block polyether 1.0%, and maleic acid-acrylic acid copolymer sodium salt 0.2%; the total amount is 2.9%

an antifreezing agent: 3.1% of ethylene glycol and 0.2% of urea; the total amount is 3.3%;

The procedure was the same as in example 5. Due to the change of the raw materials, only the suspension rate, the wet sieve test, the pourability and the lasting foam amount of the prepared product are detected, any unqualified product is judged, and other indexes are not checked. The results of the tests on the obtained products are shown in Table 10.

Results of testing thiodicarb aqueous suspensions prepared in Table 10

From the analysis results, after the dosages of the dispersing agent, the thickening agent, the antifreezing agent and the suspension stabilizer are increased, the three indexes of the suspension percentage, the wet sieve test and the lasting foam amount are qualified, and the dumping property is unqualified. The main reasons that the suspension percentage can be qualified are: although the total amount of the dispersing agent is reduced, the suspension has good suspension performance because the addition ratio of the suspension stabilizer and the thickening agent is larger than that of the suspending agent in example 5. However, the material matching is not good compared with the material ratio screened under the optimal condition, and the index of the pourability is still not qualified.

Comparative example 7 adjustment of the variety and amount of various adjuvants

1. The ingredients are measured according to the following material proportion.

Thiodicarb (100% discount) 30%

Dispersing agent: maleic acid-acrylic acid copolymer sodium salt 6.9%;

thickening agent: 0.13% of xanthan gum;

an antifreezing agent: 4.3 percent of ethylene glycol;

suspension stabilizer: polyamide formulation 0.4%;

and (3) antiseptic and mildew preventive: 0.25 percent of sodium benzoate;

defoaming agent: 0.8 percent of organic silicon additive;

pH regulator: tartaric acid 0.05%.

The water is filled to 100 percent.

2. Dissolving in primary water

Adding water accounting for 60 percent of the total amount into the dissolving kettle, sequentially adding metered xanthan gum, sodium benzoate, tartaric acid and organic silicon auxiliary agent under the stirring condition, and observing the dissolving condition of the materials from a sight glass of the dissolving kettle. The materials are dissolved for standby;

3. preparation of

Adding the metered raw medicine, secondary water (the residual water accounting for 40 percent of the total amount), the dispersant maleic acid-acrylic acid copolymer sodium salt, the glycol and the polyamide preparation into a mixing kettle for fully mixing, continuously rotating and stirring the materials in the mixing kettle by special stirring in the kettle to continuously generate a new interface, cutting, compressing and folding the materials, and stirring and mixing the materials. Mixing for 20 min, adding the primary water from the dissolving kettle to the mixing kettle, and mixing for 15 min. After the primary water is added and mixed, the materials are added into the high-shear emulsifying machine by means of gravity and the suction of the high-shear emulsifying machine for emulsification, and the materials are cut in a shearing seam through the processes of strong shearing, dispersion, impact, turbulent flow and the like generated between a rotor and a stator which rotate at high speed, and are rapidly crushed into micron-level particles. The materials sequentially enter a first sanding procedure and a second sanding procedure through a high-shear emulsifying machine, sanding is carried out for 65 minutes and 55 minutes respectively, and the two sanding procedures are detected step by step in the middle; and (5) placing in a standing tank, sampling, and analyzing various indexes. Due to the change of the raw materials, only the suspension rate, the wet sieve test, the pourability and the lasting foam amount of the prepared product are detected, any unqualified product is judged, and other indexes are not checked. The results of the tests on the obtained products are shown in Table 11.

Results of testing thiodicarb aqueous suspensions prepared in Table 11

From the analysis results, all the additives are added into a single variety, and although the total amount of the additives of each variety is in a set range, the indexes of the product except the qualified indexes are all unqualified indexes including the suspension percentage, the pourability and the lasting foam amount, and the main reason is that: compared with the material proportion screened under the optimal condition, the material matching of the method uses single quality, the matching among various auxiliary agents is poor, and three indexes of suspension rate, dumping property and lasting foam amount are not qualified.

Comparative example 8

The operation is the same as in comparative example 7, the only difference being the adjustment of the charge, namely: the dispersant is adjusted from a single variety to four varieties, and the total amount is unchanged; the variety and the addition amount of other auxiliary agents are not changed.

1. The ingredients are measured according to the following material proportion.

Thiodicarb original drug (100%) 30% dispersing agent: 1.9 percent of lauryl sodium sulfate, 1.1 percent of nonionic toilet copolymer, 2.3 percent of EO-PO block polyether and 1.6 percent of maleic acid-acrylic acid copolymer sodium salt; the total amount is 6.9%;

thickening agent: 0.13% of xanthan gum;

an antifreezing agent: 4.3 percent of ethylene glycol;

suspension stabilizer: polyamide formulation 0.4%;

and (3) antiseptic and mildew preventive: 0.25 percent of sodium benzoate;

defoaming agent: 0.8 percent of organic silicon additive;

pH regulator: tartaric acid 0.05%.

The water is filled to 100 percent.

2. Dissolving in primary water

3. preparation of

Adding the metered raw medicine, secondary water (the residual water accounting for 40 percent of the total amount), the dispersant maleic acid-acrylic acid copolymer sodium salt, the glycol and the polyamide preparation into a mixing kettle for fully mixing, continuously rotating and stirring the materials in the mixing kettle by special stirring in the kettle to continuously generate a new interface, cutting, compressing and folding the materials, and stirring and mixing the materials. Mixing for 20 min, adding the primary water from the dissolving kettle to the mixing kettle, and mixing for 15 min. After the primary water is added and mixed, the materials are added into the high-shear emulsifying machine by means of gravity and the suction of the high-shear emulsifying machine for emulsification, and the materials are cut in a shearing seam through the processes of strong shearing, dispersion, impact, turbulent flow and the like generated between a rotor and a stator which rotate at high speed, and are rapidly crushed into micron-level particles. The materials sequentially enter a first sanding procedure and a second sanding procedure through a high-shear emulsifying machine, sanding is carried out for 65 minutes and 55 minutes respectively, and the two sanding procedures are detected step by step in the middle; and (5) placing in a standing tank, sampling, and analyzing various indexes. Due to the change of the raw materials, only the suspension rate, the wet sieve test, the pourability and the lasting foam amount of the prepared product are detected, any unqualified product is judged, and other indexes are not checked. The results of the tests on the obtained products are shown in Table 12.

Results of testing thiodicarb aqueous suspensions prepared in Table 12

From the analysis results, except that the dispersing agent is added according to the total amount and the proportion of a single variety, other additives are added into the single variety, although the total amount of the addition of each variety of the other additives is within a set range, the indexes of the product except the suspension percentage and the wet sieve test are qualified, and the two indexes of the pourability and the lasting foam amount are not qualified, and the main reason is that: the dispersant is a key factor influencing the suspension rate and the suspension stability, and the added dispersant is in the optimal process parameter range according to the total amount and the proportional adding amount of a single variety, so the suspension rate index is qualified. However, compared with the material proportion screened under the optimal condition, the material matching of the method uses single quality, the matching property among various auxiliary agents is poor, and the two indexes of the pouring property and the lasting foam amount are still not qualified, so that the product is unqualified.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement or improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. The thiodicarb aqueous suspension is characterized by comprising the following components, by weight, 28.5-31.5% of thiodicarb, 12.1-14.6% of an auxiliary agent, and the balance of water;

2. The thiodicarb aqueous suspension concentrate of claim 1, wherein the dispersant is a mixture of four surfactants, i.e., sodium lauryl sulfate, a nonionic comb copolymer, EO-PO block polyether, and sodium salt of maleic acid-acrylic acid copolymer; preferably, the nonionic comb copolymer is polyoxyethylene nonylphenol selected from polyoxyethylene nonylphenol NP-4, polyoxyethylene nonylphenol NP-7, polyoxyethylene nonylphenol NP-9 and polyoxyethylene nonylphenol NP-10, and more preferably polyoxyethylene nonylphenol NP-10.

3. The thiodicarb aqueous suspension of claim 1 wherein the thickener is a mixture of xanthan gum, magnesium aluminum silicate and carboxymethylcellulose.

4. The thiodicarb aqueous suspension of claim 1 wherein the anti-freeze agent is a mixture of ethylene glycol and urea;

the suspension stabilizer is a mixture of polyamide preparation and EDTA;

the antiseptic and mildew preventive is a mixture of sodium benzoate and 1, 2-benzisothiazolin-3-one;

the defoaming agent is organic silicon assistant and C₈-C₁₀A mixture of fatty alcohol compounds;

the pH regulator is tartaric acid.

5. The thiodicarb aqueous suspension concentrate of claim 2, wherein the dispersant comprises sodium dodecyl sulfate in an amount of 1.3-2.0%, a nonionic toilet copolymer in an amount of 0.9-1.5%, EO-PO block polyether in an amount of 0.9-2.3%, maleic acid-acrylic acid copolymer sodium salt in an amount of 0.8-1.6%, and the total amount of the four dispersant materials in an amount of 4.8-6.9%.

6. The thiodicarb aqueous suspension of claim 3 wherein the thickening agent comprises xanthan gum in an amount of 0.01 to 1.0%, magnesium aluminum silicate in an amount of 0.2 to 1.2%, carboxymethylcellulose in an amount of 0.01 to 1.0%, and a total of three materials in an amount of 0.2 to 3%.

7. The thiodicarb aqueous suspension concentrate of claim 4, wherein the antifreeze agent comprises 3-5% ethylene glycol, 0.1-1.5% urea, and 3.5-5.5% total of the two materials;

8. A preparation method of thiodicarb suspending agent is characterized by comprising the following steps:

step 1, batching: accurately metering the ingredients of the materials in the proportions provided in any one of claims 5 to 7;

step 3, secondary water dissolution: adding the metered active compound thiodicarb, the rest water accounting for 40% of the total amount and other auxiliary agents into a mixing kettle, stirring and mixing, adding the primary mixed material in the dissolving kettle in the step 2 into the dissolving kettle after fully mixing for 15-30 minutes, and continuously stirring and mixing for 10-15 minutes to obtain a secondary mixed material;

step 4, shearing: transferring the secondary mixed material obtained in the step (3) to a high-shear emulsifying machine, and shearing and crushing the secondary mixed material into micron-sized particles;

step 5, sanding;

step 6, standing, sampling, analyzing and inspecting;

and 7, packaging.

9. The method for preparing the thiodicarb suspending agent as claimed in claim 8, wherein the suspending stabilizer, the thickener, the preservative and anti-mildew agent, the pH regulator, the defoamer and the antifreeze added in the step 2 are EDTA, xanthan gum, carboxymethyl cellulose, sodium benzoate, tartaric acid, organosilicon adjuvant and urea respectively.

10. The method for preparing the thiodicarb suspending agent according to claim 8, wherein in the step 5, the first sanding step comprises: sanding the particles obtained in the step (4) for 30-80 minutes by using a horizontal sand mill, wherein the rotating speed of the horizontal sand mill is 1100 r/min, and the grain size is not more than 5 mu m after sampling and analyzing; then carry out the second sanding process: and sanding for 20-60 minutes by using a horizontal sand mill, wherein the rotating speed of the horizontal sand mill is 1440 rpm, and the grain size of the sampled and analyzed grains after sanding is not more than 3 mu m.