The Liquid R&D Room is mainly engaged in R& D of pesticide formulations such as SC, FS, EW, ME, SE, OF, SL, ULV and CS (capsule suspension). The tenet is as follows: (1) Selecting pesticides according to the pesticide application information of domestic and foreign pesticide circle and plant protection circle, and carrying out technical reserve of new formulations and new varieties; (2) Providing product information of processable pesticides and expanding processing service; (3) External technical cooperation and exchange, especially on application of domestically advanced auxiliaries.
Rapid SC Development of the Company:
SC, also referred to as water suspension concentrate and colloidal suspension agent, is formed by dispersing solid technical materials insoluble or poorly soluble in water into water with the action of surfactants and other auxiliaries to make them form a uniform and stable suspension system via mechanical force. SC is mainly composed of technical material, wetting agent, dispersant, thickener, antifreeze, pH regulator, defoamer and water. However, the preparation formulas are different for different varieties and specifications. Therefore, screening of reasonable preparation formula is an important link for SC R&D.
In recent years, SC has been developing the fastest among the domestic and foreign pesticide formulations, and tends to gradually substitute traditional WP formulations. Compared with WP, SC is characterized by fine granule (2-5um), desirable fluidity, dispersion, spread property and biological activity, high suspension rate (90-95%), desirable adhesiveness and spread property resisting rain washing, absence of solvent, environmentally-friendliness, high safety and low processing expenses. In recent years, considerable part of high-efficient and ultra high efficient pesticides newly introduced in the world has been prepared into SC formulation. At present, the company has processed more than 100 SC varieties, and both the varieties and processing volumes are increasing year by year.
In order to ensure SC product properties, the Standards and Codes for Pesticide Suspension Concentrate Products, the standard of the Chemical industry of China prescribes that general pesticide SC products should control nine indexes, i.e. content of active ingredients, relative impurity limit, pH or pH range, suspension rate pourability, wet sieve test, permanent foaming capacity, low temperature and heated-storage stability. These indexes may ensure content of active ingredients and some physical characteristics of pesticide SC products. However, in consideration of ensuring better stability and application property, the following test items are generally added, e.g.
1. Particle size distribution, with the best particle size ranging from 0.3 to 0.5um.
2. Determination of centrifugal stability, with water segregation rate being controlled at <=5%;
3. Viscosity determination. As one of the important factors influencing stability of pesticide SC, viscosity is an important technical index of SC. Under the precondition of controlling formulation stability, viscosity is determined with a rotational viscometer.
Control over SC physical stability:
Control over SC physical stability is centralized in preventing excessive stratification, thickness and caking due to precipitation, inflation and aggregation of granules of formulations. During SC processing process for many years, we have accumulated certain experience, which as mainly as follows:
1) Scientific screening of polymeric dispersants and composite dispersants to make them have desirable wetting property, absorbability and deflocculation function to technical materials, disintegrate agglomerate formed by powder, maintain ground granules in colloid stability or weak flocculation state and suppress crystal growth.
2) Preparation of SC requires application of quality-stable solid pesticides insoluble in water or those with the smallest water solubility, (<=70mg/L in general). We do not accept, in principle, solid technical materials with larger water solubility required by customers.
3) The company has applied laser particle sizer in SC particle size analysis rather early in China. SC stability is analyzed by controlling SC particle size and size distribution.
4) Influence of storage temperature on SC physical property. Before processing, get to know the destination countries of SC exportation, transportation and storage conditions from customers and adjust the formulas of antifreeze or stabilizer according to specific conditions to test the stability through experiment of hot and cold storage.
5) Flexibly handle pre-crushing technology, grinding technology and modulation technology according to characteristics of different products so as to control the particle size within 2-5um. Select suitable stabilizer, deflocculant, thickener and so on, and prohibit particle precipitation and crystal inflation of technical materials of SC through product viscosity index and centrifugal precipitation experiment.
With constant emergence of new pesticide SC formulations both at home and abroad, the company will strengthen R&D and make an effort to provide more and better SC products.
Water FS is a formulation under key development by the company:
As a kind of pesticide preparation with film-forming characteristics used for coating of plants and other plant seeds, seed coating agent is generally prepared by technical material, dispersant, wetting agent, film former, pH regulator, antifreeze, defoamer, other auxiliaries and water. It can be directly coated on the seed surface after dilution to form a protective film with certain strength and permeability, so it is named as seed coating agent.
Seed coating agent and seed treatment agent are two different concepts. Seed treatment agent is divided into seed dressing agent, multi-seed agent and seed coating agent. Seed dressing agent and seed soaking agent belong to a method of field pesticide application, but not a kind of pesticide formulation. Seed coating agent is not required within nearly 45 days at bud stage and seeding stage due to its characteristics of coating of seeds, and the dosage is only about 1/50 of field pesticide application. Therefore, it is called the new pesticide formulation saving the most pesticide.
Seed coating agent can, according to pesticide formulation, be divided water flowable seed coating agent (FS), water-emulsion seed coating agent (EWS), suspended emulsion seed coating agent (SES), micro-capsule seed coating agent (CS), dry flowable seed coating agent (DFS), water dispersible granule type seed coating agent (WGS), etc.
As a kind of seed coating formulation most widely applied in the maximum volume at home and abroad, FS is a special SC which super crushes solid pesticides and other auxiliary components into less than 4um.
FS is the key pesticide formulation developed by the company in recent years. There are more than 20 relatively stable export processing varieties. In recent years, FS has received considerable attention thanks to its high efficiency, economy, safety, long pesticide duration and multi-function, and account for a very large proportion of the seed treatment formulation in Europe. In the world seed treatment market, the sales volume in Europe accounts for 60%. Among the seed treatment products, 70% belongs to bactericide. The conventional processing and export varieties and export regions of the company are basically consistent with the data.
Preparation and formula of FS are similar to those of SC, and the main difference is that FS contains more components. Moreover, it contains more sufficient binder or film former, and is generally added with warning coloration. FS is required to have better rheological characteristic than SC so as to ensure the uniformity of seed coating. Imported dispersant and film former are generally used in FS formulation.
The FS varieties in larger export processing volume of the company include Tebuconazole, flutriafol, Carbofuran, Difenoconazole, Imidacloprid, Metalaxyl, Thiamethoxam, Tebuconazole + penycuron, Imidacloprid + penycuron, Carboxin + Thiram, Flutriafol + triabendazole + imazalil, Tebuconazole + imazalil, etc. The colors are scarlet and rose bengal, and the color depth is determined according to customer demands.
Difference among SL, Me and AS:
Among the processing of pesticides for export, domestic and foreign customers and domestic pesticide foreign trade companies always confuse three different formulations of SL, AS and ME during order inquiry. Though these three formulations are very similar in appearance, and all are clear and transparent, they are greatly different from each other.
1) SL is a kind of pesticide formulation soluble in water during application which is prepared by technical material slightly soluble in water with a large quantity of hydrophilicity polar solvent, auxiliary with cosolvent and emulsifier, e.g. Imidacloprid 200g/l SL, Acetamiprid 200g/l SL, Tebuconazole 250g/l SL (or called silimar SL), Cyproconazole 250g/l SL, monocrotophos 400g/l SL and so on.
The most remarkable characteristic of SL is to make much EC originally difficult to prepare or with very low content soluble in water to become soluble in water and have strong penetrability by using a great deal of hydrophilic polar solvent and SL formulation. Since the formulation is not environmentally-friendly, it is unsuitable for being promoted and applied widely in field plants and edible fruits and vegetables. It is generally applied to specific control object. For example, Imidacloprid SL is mainly used for disinsection and protection of animal furs and trees.
2) ME is the transparent or translucent solution which is formed by liquid pesticide prepared with liquefied pesticide or with solvent dispersing in aqueous solution with a large amount of surfactant. Liquefied pesticide forms fine particle (0.01-0.1um) under the action of surfactant with relatively high concentrate. It “gets into” the super-molecule formed by excessive surfactant, and the liquid droplet of fine particle is uniformly and stably distributed in water. ME is the limit of pesticide emulsification. However, it is not milky. ME is listed among water dispersible formulations because it takes water as medium, substituting a part of solvent, which is the difference between it and EC.
ME is featured by desirable formulation stability, high efficacy (The efficacy is generally 5-10% higher than that of EC due to overuse of emulsifier) and relatively simple preparation technology. However, since it uses a lot of hydrophilic solubilizer and such organics as amides, ketones straight-chain or multi-chain alcohol, its acute toxicity exceeds that of xylene, and it is more liable to permeate into plant, farmland and water source, and it is uneasy to remove and separate, bringing new threat to the environment and food safety. Therefore, ME is a kind of undesirable formulation in foreign countries, which can be explained by the absence of ME variety among the formulations registered in China by foreign pesticide enterprises. The company has been engaging in pesticide import and export for many years, and has never received foreign order inquiry about ME pesticides. Therefore, the company does not take ME as the key R& D item.
3) AS is a kind of solution prepared by technical material directly soluble in water but indecomposable in water and surfactant and water. Thus the concentration of AS agent, also called pesticide technical material, depends on water solubility of technical material. In general condition, it is in the maximum solubility, and should be diluted with water in application, e.g. 40% gyphosate solution, 20% Paraquat aqueous solution and 2% avermectin. The most remarkable characteristic thereof is that it does not contain organic solvent. The domestic pesticide registered formulation is AS. However, speaking from soluble solution, water is also a kind of solvent, so AS is generally designated as SL customarily.
ULV is a new formulation developing the fastest in China:
ULV is a kind of specially prepared oil solution. It is sprayed into 70~120grn fine fogdrop on the ground or on plane and can uniformly distribute on the surface of plant stems and leaves, thus playing an effective role of controlling illness and insect pest. It is featured by small dosage, good efficacy, high work efficiency, low controlling expenses and without application of water. Its formula is mainly composed of solvent besides technical material. The solvent applied is required to have capacity of solving technical material, small volatility and flash point not lower than 70℃. Sometimes the formula is required to adding other auxiliaries such as solubilizer, viscosity reductant, stabilizer, electrostatic agent, etc.
The formulation has the following characteristics compared with conventional spray:
(1) Small spray volume, 60~330ml/mu (1 hectare=15mu), being one in hundreds of conventional spray volume.
(2) Slim fogdrop. Fogdrop diameter is 70~100um, while conventional fogdrop diameter is 200~300um. Pesticide liquid has a high coverage rate, desirable permeability and high efficacy.
(3) Spray liquid concentration and work efficiency is several hundred times and tens times higher than that of conventional spray respectively.
(4) Conventional spray liquid takes water as carrier, while ULV takes oily solvent of high boiling point as carrier. ULV has a better resistance to rain washing and long efficacy period.
ULV varieties processed for export by the company include Deltamethrin 25g/L ULV, Lambda-Cyhalothrin 40g/L ULV, Fenitrothion 600 g/L ULV, Malathion 950 g/L ULV, etc.
New Development of SE of the company:
Among water-dispersible pesticide formulations, SE, a new formulation having emerged in the world in recent years, is combined by mixture of liquefied pesticide insoluble in water or that of low melting point with solvent and solid technical material insoluble in water. It can be regarded as the combination of SC and EW formulations in terms of formulation. However, the formulation is not the simple combination of two formulations, but the combination of two or more insoluble pesticide active components into multiphase and dispersion in water so as to form a stable formulation of emulsion dispersion system. The advantages of the formulation are to provide products of wider spectra, avoid the defect of tank and stick, and reduce times of spraying over the plants, thus saving time and expenses. However, the biggest difficulty of the formulation is to establish the stability of the suspension and aqueous emulsion composed by several active components, which is the most important difficult problem of SE formulation development. The unstable state is mainly represented by stratification and precipitation during storage period, especially in case of temperature rise, separation of solid granules and oil drops, aggregation of oil drop and growth of impure flocculation and crystallization between solid granules and oil drops. Since SE has the cross influence of various unstable factors existing in SC and EW, so it is more difficult to process stable SE formulation than stable SC and EW.
In SE R&D, stability of SE formulation is generally explored and solved through the following means:
1) As for processed varieties, technical materials are required to be liquid ones or ones with low melting point, indecomposable in water but with certain solubility.
2) Selecting the most effective dispersant to prevent flocculation and aggregation.
3) Selecting the best thickener and colloid stabilizer to reduce stratification and precipitation.
4) Applying advanced foreign high-shear homogeneous system to make the droplet diameter of emulsion distributed rather narrow, thus effectively solving the stability of emulsion in terms of preparation.
5) Applying advanced laser particle sizer to detect droplet distribution so as to provide necessary detection means for EW R&D and processing.
Thanks to many years of practical pesticide foreign trade and processing, we have initially accumulated some experience and undertaken processing and export of some varieties, e.g. alachlor 350g/l +200g/l, atragine SE, Acetochlor 200g/l + atragine 200g/L SE, Buprofezin 300g/l + Profenofos 50g/l SE, etc.
We sincerely hope to get help from more domestic and foreign formulation experts, foreign auxiliaries corporations and scientific research institutions. We also hope that customers will give us more chance of practice and make concerted efforts to promote the development of new SE formulation.
R&D and processing varieties of EW:
EW is a kind of pesticide formulation with appearance of milky white liquid which is formed by dispersing liquid pesticide mixed by liquid or with solvent in water in 0.5-1.5um droplet. Since the formulation substitutes water for one copy or all organic solvents, EW replaces EC as a new excellent environmentally-friendly pesticide formulation. With EW R&D and rapid development of pesticide registration and application in China and foreign countries, the company has started EW R&D as well as export and processing of relatively mature EW varieties ever since 2004. At present, it can process almost 20 EW varieties, and the number is gradually increasing.
The difficulty of EW processing is that the formulation belongs to unstable system in thermodynamics, and it can form naturally as long as the conditions for solubilizer and emulsifier are ensured. EW requires high-strength shearing, stirring and homogenization to prepare technical material into 0.5-1.5um droplet, and make it disperse in aqueous solution and maintain the state of stable storage. Therefore, prohibition of stratification (precipitation) of liquid phase and aqueous phase as well as flocculation, aggregation and expansion of droplets is the difficulty for preparing stable EW system. AS the corporate export processing business is characterized by high uncertainty of foreign orders, small processing quantity of each batch and urgent need of goods, it is necessary for us to make more technical reserve of EW varieties and strengthen exchange and cooperation with scientific research units and foreign auxiliaries corporations so as to promote R&D of EW varieties and gradually expand processing business.
EW processing varieties include Acetochlor 400g/L EW, Beta-Cypermethrin 50g/L EW, Butachlor 400g/L EW, Chlorpyrifos 400g/L EW (300g/L), Deltamethrin 25g/L EW, Dicofol 200g/L EW, Fenoxaprop-p-Ethyl 69g/L EW (75g/L), Lambda-Cyhalothrin 25g/L EW (50g/L), Tebuconazole 125g/L EW (250g/L), Oxadiazon 120g/L EW, Penconazole 200g/L EW, Prochloraz 450g/L EW (250g/L), etc.
Nicosulfuron OF is the knockout product developed by the company through processing practice of many years:
As a kind of suspension concentrate, OF is, compared with SC, a stable suspension system with oil as dispersion medium. OF pesticide varieties, most of which are active ingredients of pesticides, are apt to decompose or become unstable in water but show good or excellent dispersion and chemical stability in oil. Being prepared with SC processing technology including solid pesticide, wetting dispersant, texturing agent (rheological agent), antifreeze, pH regulator, thickener, oil agent, OF enjoys advantages of a better adhesiveness and spread property than SC, easier adhesion to waxy or smooth leaf surface and resistance to rain washing, which is the reason why the dosage of pesticide active components of OF is generally lower than that of other formulations.
The main processing variety of the company is Nicosulfuron OF. We have researched, developed and processed the formulation for six years, having accumulated rich formula and preparation experience, especially having made significant achievements in researching chemical and physical stability. In case of hot storage of two weeks or natural storage of two years of the product, the decomposition rate of the active ingredients thereof reaches the level of the same products of Japan. In terms of physical stability, the stratification problem intentionally required by domestic and foreign customers can be controlled within 5~10%, with desirable dispersion, fluidity and emulsion stability. The variety thus becomes the knockout product of external processing of the company, having won affirmation and appraisal from customers at home and abroad.